(cherry picked from commit cfb7f800)

* Fix typos and formatting

* Add Solidity release dates: releases-stability

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Co-authored-by: Paolo Dibitonto <p.dibitonto@almaviva.it>
Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* Update all non-major dependencies

* disable solhint reason-string rule

Co-authored-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* chore: fix code style parameters in Event

* chore: update code style for events

Co-authored-by: Alan Lu <alanlu1023@gmail.com>
Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>
Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

This reverts commit c801c8d2.

* Update contract pragmas to solidity 0.7

* Remove internal declaration on constructors

* Reference SafeMath explicitely

* Remove public constructor declaration from abstract contracts

* Remove public constructor declaration from non-abstract contracts

* docs: add notes explaining presets

* fix links for mint function

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* feat: use extcodesize for isContract to reduce gas

* feat: add changelog entry

Co-authored-by: Renovate Bot <bot@renovateapp.com>

* add readme notices

* remove period after url

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>