Update README.md to fix typo

Typo: "tToken"

* switch to using Context internally

* add context import

* Add smoke test to make sure enabling GSN support works

* Update test/GSN/ERC721GSNRecipientMock.test.js

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

* Upgrade truffle

* add missing awaits

* Revert "Upgrade truffle"

This reverts commit f9b0ba9019650fdbf8919a33e6fba834689e6b04.

* GSN support

Add base Context contract

Add GSNContext and tests

Add RelayHub deployment to tests

Add RelayProvider integration, complete GSNContext tests

Switch dependency to openzeppelin-gsn-provider

Add default txfee to provider

Add basic signing recipient

Sign more values

Add comment clarifying RelayHub's msg.data

Make context constructors internal

Rename SigningRecipient to GSNRecipientSignedData

Add ERC20Charge recipients

Harcode RelayHub address into GSNContext

Fix Solidity linter errors

Run server from binary, use gsn-helpers to fund it

Migrate to published @openzeppelin/gsn-helpers

Silence false-positive compiler warning

Use GSN helper assertions

Rename meta-tx to gsn, take out of drafts

Merge ERC20 charge recipients into a single one

Rename GSNRecipients to Bouncers

Add GSNBouncerUtils to decouple the bouncers from GSNRecipient

Add _upgradeRelayHub

Store RelayHub address using unstructored storage

Add IRelayHub

Add _withdrawDeposits to GSNRecipient

Add relayHub version to recipient

Make _acceptRelayedCall and _declineRelayedCall easier to use

Rename GSNBouncerUtils to GSNBouncerBase, make it IRelayRecipient

Improve GSNBouncerBase, make pre and post sender-protected and optional

Fix GSNBouncerERC20Fee, add tests

Add missing GSNBouncerSignature test

Override transferFrom in __unstable__ERC20PrimaryAdmin

Rhub address slot reduced by 1

Rename relay hub changed event

Use released gsn-provider

* move gsn to all caps

* update to gsn contracts in solidity/master

* Adapt for ethereum-package

* update gsn related packages

* update dependencies to match contracts repo

* remove mocha bail option

* add changelog entry

* add constructors to mocks

* use unstructured storage for bouncer implementations

* Release 2.2.1

* Use caret for peer dependency

* Change import path from zos-lib to upgrades in all contracts

* Update readme with new naming

* Update package and deps names

* Change path to initializable in AST of networks.jsons

* Migrate manifest version

* Use new oz file locations

* Rename in ERC20Migrator comments

* Update SDK install instructions in README

* Update gitignore to use new session file name

* trigger CI

* Fixes to readme and package version

* Use 2.5.0 release of OpenZeppelin SDK

Documentation: update README links

Co-Authored-By: Nicolás Venturo <nicolas.venturo@gmail.com>

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.0.12 to 4.1.2.
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/wycats/handlebars.js/blob/master/release-notes.md)
- [Commits](https://github.com/wycats/handlebars.js/compare/v4.0.12...v4.1.2)

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.6.1 to 3.13.1.
- [Release notes](https://github.com/nodeca/js-yaml/releases)
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nodeca/js-yaml/compare/3.6.1...3.13.1)

v2.2.0

* Transaction Malleability:
If you allow for both values 0/1 and 27/28, you allow two different
signatures both resulting in a same valid recovery. (r,s,0/1) and
(r,s,27/28) would both be valid, recover the same public key and sign
the same data. Furthermore, given (r,s,0/1), (r,s,27/28) can be
constructed by anyone.

* Transaction Malleability:
EIP-2 still allows signature malleabality for ecrecover(), remove this
possibility and force the signature to be unique.

* Added a reference to appendix F to the yellow paper and improved
comment.

* better test description for testing the version 0, which returns
a zero address

* Check that the conversion from 0/1 to 27/28 only happens if its 0/1

* improved formatting

* Refactor ECDSA code a bit.

* Refactor ECDSA tests a bit.

* Add changelog entry.

* Add high-s check test.

* Add extcodesize check to SafeERC20.

* Clarify some comments.

* Replace inline assembly with Address.sol.

* Add TimedCrowdsale::_extendTime

* Add tests for TimedCrowdsale extending method

* Reverse event arguments order

* Rename method argument

* Refactor TimedCrowdsale test

* Simplify TimedCrowdsaleImpl

* Fix extendTime method behaviour to deny TimedCrowdsale re-opening after it was ended

* Append chengelog

* Update CHANGELOG.md

Co-Authored-By: k06a <k06aaa@gmail.com>

* Update contracts/crowdsale/validation/TimedCrowdsale.sol

Co-Authored-By: k06a <k06aaa@gmail.com>

* Improve tests

* Add guard to ERC20Migrator migrate function

* Add tests for premature migration in ERC20Migrator

These tests apply to the new guard condition, but they don't
fail without it, since the functions revert anyway.
They are added for completeness and to ensure full code coverage.

* Use context block around premature migration tests

We should use context blocks for situational details
and describe for features or functions.

* rename previous audit to date it was performed

* add latest audit

* add note about latest audit in README

Using "a" instead of "an" makes this consistent with the comment on `allowance`.

* Add no-return-data ERC20 support to SafeERC20.

* Add changelog entry.

* Replace abi.encodeWithSignature for encodeWithSelector.

* Remove SafeERC20 test code duplication.

* Replace assembly for abi.decode.

* Fix linter errors.