Update Node package dependencies & GitHub Action versions

In GH-32 [1] all ESLint packages and dependencies have been updated to
the latest version.
This commit updates all repository development packages and GitHub
Actions to the latest versions and adapts to the changes:

- Updated to ESLint v7 - bumped package version from `v6.2.0` to
  `v7.23.0` [2]. See GH-32 [1] and the official v7 migration guide [3]
  for more details.
- Removed `--ext` option for ESLint tasks - as of ESLint v7, files
  matched by `overrides[].files` are now linted by default [4] which
  makes it obsolete to explicitly define file extensions like `*.js`.
- del-cli [5] - Bumped minimum version from `v2.0.0` to `v3.0.1` [6].
- eslint-config-prettier [7] - Bumped version from `v6.1.0` to
  `v8.1.0` [8].
- eslint-plugin-prettier [9] - Bumped minimum version from `v3.1.0` to
  `v3.3.1` [10].
- eslint-plugin-import [11] - Bumped minimum version from `v2.18.2` to
  `v2.22.1` [12].
- husky [13] - Bumped minimum version from `v3.0.4` to `v6.0.0` [14].
  This also includes some breaking changes that require migrations.
  Executed the official migration CLI to automatically migrate from v4
  to v6:
  `npx husky-init && npm exec -- github:typicode/husky-4-to-6
  --remove-v4-config`
- lint-staged [15] - Bumped minimum version from `v9.2.3` to
  `v10.5.4` [16].
- prettier [17] - Bumped minimum version from `v1.18.2` to
  `v2.2.1` [18].
- remark-cli [19] - Bumped minimum version from `v7.0.0` to
  `v9.0.0` [20].

[1]: #32
[2]: eslint/eslint@v6.2.0....v7.23.0
[3]: https://eslint.org/docs/user-guide/migrating-to-7.0.0
[4]: https://eslint.org/docs/user-guide/migrating-to-7.0.0#lint-files-matched-by-overridesfiles-by-default
[5]: https://github.com/sindresorhus/del-cli
[6]: sindresorhus/del-cli@v2.0.0...v3.0.1
[7]: https://github.com/prettier/eslint-config-prettier
[8]: prettier/eslint-config-prettier@v6.1.0...v8.1.0
[9]: https://github.com/prettier/eslint-plugin-prettier
[10]: prettier/eslint-plugin-prettier@v3.1.0...v3.3.1
[11]: https://github.com/benmosher/eslint-plugin-import
[12]: import-js/eslint-plugin-import@v2.18.2...v2.22.1
[13]: https://github.com/typicode/husky
[14]: typicode/husky@v3.0.4...v6.0.0
[15]: https://github.com/okonet/lint-staged
[16]: typicode/husky@v9.2.3...v10.5.4
[17]: https://github.com/prettier/prettier
[18]: typicode/husky@v1.18.2...v2.2.1
[19]: https://github.com/remarkjs/remark/releases
[20]: typicode/husky@v7.0.0...v9.0.0

Co-authored-by: Sven Greb <[email protected]>

GH-33

Author: arcticicestudio

.husky/.gitignore

@@ -0,0 +1 @@
+_

.husky/pre-commit

@@ -0,0 +1,4 @@
+#!/bin/sh
+. "$(dirname "$0")/_/husky.sh"
+
+yarn run lint-staged

.huskyrc.js

@@ -25,30 +25,32 @@
     "yarn": "^1.17.3"
   },
   "scripts": {
-    "clean": "del build",
+    "clean": "del build/",
     "docs:build": "gitbook install src && gitbook build src build/docs",
     "docs:dev": "yarn docs:build && gitbook serve src build/docs",
     "format": "npm-run-all format:pretty format:fix",
-    "format:fix": "eslint --fix --ext .js .",
+    "format:fix": "eslint --fix .",
     "format:pretty": "prettier --write \"**/*.{js,json,md,yml}\"",
     "lint": "npm-run-all lint:*",
-    "lint:js": "eslint --ext .js .",
+    "lint:js": "eslint .",
     "lint:md": "remark --no-stdout . \".github/**/*.md\"",
     "lint:pretty": "prettier --check \"**/*.{js,json,md,yml}\"",
+    "prepare:husky": "husky install",
+    "prepare": "npm-run-all prepare:*",
     "test": "yarn workspaces run test"
   },
   "devDependencies": {
-    "del-cli": "2.0.0",
-    "eslint": "6.2.0",
-    "eslint-config-prettier": "6.1.0",
-    "eslint-plugin-import": "2.18.2",
-    "eslint-plugin-prettier": "3.1.0",
+    "del-cli": "^3.0.1",
+    "eslint": "^7.23.0",
+    "eslint-config-prettier": "^8.1.0",
+    "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-prettier": "^3.3.1",
     "gitbook-cli": "2.3.2",
-    "husky": "3.0.4",
-    "lint-staged": "9.2.3",
-    "npm-run-all": "4.1.5",
-    "prettier": "1.18.2",
-    "remark-cli": "7.0.0",
+    "husky": "^6.0.0",
+    "lint-staged": "^10.5.4",
+    "npm-run-all": "^4.1.5",
+    "prettier": "^2.2.1",
+    "remark-cli": "^9.0.0",
     "remark-preset-lint-arcticicestudio": ">=0.3.0 <1.0.0"
   },
   "private": true,