Update dependencies + configure Dependabot (#1931)

* update dependencies with npm update

* add dependabt config

* change dependabot schedule to weekly

* configure dependabot to increase package.json versions

.dependabot/config.yml

+version: 1
+
+update_configs:
+  - package_manager: "javascript"
+    directory: "/"
+    update_schedule: "weekly"
+    version_requirement_updates: "increase_versions"

package.json

@@ -45,27 +45,27 @@
   "homepage": "https://github.com/OpenZeppelin/openzeppelin-contracts",
   "devDependencies": {
     "@openzeppelin/gsn-helpers": "^0.1.9",
-    "@openzeppelin/gsn-provider": "^0.1.6",
+    "@openzeppelin/gsn-provider": "^0.1.8",
     "chai": "^4.2.0",
-    "concurrently": "^4.1.0",
+    "concurrently": "^4.1.2",
     "eslint": "^4.19.1",
     "eslint-config-standard": "^10.2.1",
-    "eslint-plugin-import": "^2.13.0",
+    "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-mocha-no-only": "^1.1.0",
     "eslint-plugin-node": "^5.2.1",
     "eslint-plugin-promise": "^3.8.0",
     "eslint-plugin-standard": "^3.1.0",
-    "ethereumjs-util": "^6.0.0",
-    "ganache-cli": "^6.4.1",
+    "ethereumjs-util": "^6.1.0",
+    "ganache-cli": "^6.7.0",
     "ganache-cli-coverage": "https://github.com/frangio/ganache-cli/releases/download/v6.4.1-coverage/ganache-cli-coverage-6.4.1.tgz",
     "http-server": "^0.11.1",
     "lodash.startcase": "^4.4.0",
     "micromatch": "^4.0.2",
-    "nodemon": "^1.19.0",
+    "nodemon": "^1.19.3",
     "openzeppelin-test-helpers": "^0.4.3",
     "solhint": "2.1.0",
     "solidity-coverage": "github:rotcivegaf/solidity-coverage#5875f5b7bc74d447f3312c9c0e9fc7814b482477",
-    "solidity-docgen": "^0.3.0-beta.4",
-    "truffle": "^5.0.34"
+    "solidity-docgen": "^0.3.4",
+    "truffle": "^5.0.39"
   }
 }