Update Node packages (#75)

Updated all Node packages to their latest versions:

- husky [1] — Bumped minimum version from `v4.3.0` to `v6.0.0` [2].
  This also includes some breaking changes that require migrations.
  Run 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 [3] — Bumped minimum version from `v10.5.1` to
  `v10.5.4` [4].
- remark-cli [5] — Bumped minimum version from `v8.0.1` to
  `v9.0.0` [6].
- Validated and fixed/improved matches after running formatting and
  linting tools with their latest versions.

[1]: https://github.com/typicode/husky
[2]: typicode/husky@v4.3.0...v6.0.0
[3]: https://github.com/okonet/lint-staged
[4]: typicode/husky@v10.5.1...v10.5.4
[5]: https://github.com/remarkjs/remark/releases
[6]: typicode/husky@v8.0.1...v9.0.0

Closes GH-74

.husky/.gitignore

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

.husky/pre-commit

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# Copyright (c) 2020-present Sven Greb <development@svengreb.de>
+# This source code is licensed under the MIT license found in the LICENSE file.
+
+# The configuration for husky.
+#
+# References:
+#   1. https://github.com/typicode/husky
+
+. "$(dirname "$0")/_/husky.sh"
+
+npm exec lint-staged

package.json

@@ -22,14 +22,16 @@
     "format:pretty": "prettier --write .",
     "lint": "run-s lint:*",
     "lint:md": "remark --no-stdout . \".github/**/*.md\"",
-    "lint:pretty": "prettier --check ."
+    "lint:pretty": "prettier --check .",
+    "prepare:husky": "husky install",
+    "prepare": "run-s prepare:*"
   },
   "devDependencies": {
-    "husky": "^4.3.0",
-    "lint-staged": "^10.5.1",
+    "husky": "^6.0.0",
+    "lint-staged": "^10.5.4",
     "npm-run-all": "^4.1.5",
     "prettier": "^2.2.1",
-    "remark-cli": "^8.0.1",
+    "remark-cli": "^9.0.0",
     "remark-preset-lint-arcticicestudio": ">=0.3.0 <1.0.0"
   }
 }