feat(CI): add the GitHub Super Linter

The GitHub Super Linter is a more robust and better supported
tool than the current GitHub Actions we are using.

Running these checks:

ERROR_ON_MISSING_EXEC_BIT: true
VALIDATE_BASH: true
VALIDATE_BASH_EXEC: true
VALIDATE_EDITORCONFIG: true
VALIDATE_MARKDOWN: true
VALIDATE_SHELL_SHFMT: true
VALIDATE_YAML: true

https://github.com/marketplace/actions/super-linter
https://github.com/github/super-linter

Added the GitHub Super Linter badge to the README.

Also updated the pre-commit framework and added
more documentation on pre-commit.

Added one more pre-commit check: check-executables-have-shebangs

Added one extra check for merge conflicts to our
GitHub Actions.

EditorConfig and Markdown linting.

Minor grammar and spelling fixes.

Update linter.yml

.github/linters/.ecrc

@@ -0,0 +1,12 @@
+{
+    "verbose": false,
+    "ignore_defaults": false,
+    "exclude": ["oss-fuzz/", "src/"],
+    "disable": {
+        "end_of_line": false,
+        "trim_trailing_whitespace": false,
+        "insert_final_newline": false,
+        "indent_size": true,
+        "indent_style": true
+   }
+}

.github/linters/.markdown-lint.yml

@@ -0,0 +1,12 @@
+MD001: false
+MD003: false
+MD005: false
+MD007: false
+MD010: false
+MD013: false
+MD014: false
+MD024: false
+MD025: false
+MD026: false
+MD040: false
+MD046: false

.github/linters/.yaml-lint.yml

@@ -0,0 +1,8 @@
+---
+
+extends: default
+
+rules:
+  document-start: disable
+  line-length: disable
+  truthy: false

.github/workflows/lint.yml

@@ -1,52 +1,32 @@
-name: ❄️ Lint
+name: Lint
 
 on: [pull_request]
 
 jobs:
-  markdownlint:
-    name: 🍸 Markdown
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - name: 🚀 Use Node.js
-        uses: actions/setup-node@v2.1.5
-        with:
-          node-version: '14'
-      - run: npm install -g markdownlint-cli@0.27.1
-      - run: markdownlint '**/*.md'
   misspell:
-    name: 🥛 Check Spelling
+    name: Check Spelling
     runs-on: ubuntu-latest
     steps:
-      - name: 🍒 Check Out
+      - name: Check Out
         uses: actions/checkout@v2
-      - name: 🍅 Install
+      - name: Install
         run: |
           wget -O - -q https://git.io/misspell | sh -s -- -b .
-      - name: 🌶️ Misspell
+      - name: Misspell
         run: |
           git ls-files --empty-directory | xargs ./misspell -error
+  merge-conflict:
+    name: Merge Conflict
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Check merge conflict
+        run: |
+          grep "^<<<<<<< HEAD" $(git ls-files | xargs) && exit 1 || true
   trailing-whitespace:
-    name: 🧋 Trailing whitespace
+    name: Trailing whitespace
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: 🧹 Check for trailing whitespace
+      - name: Check for trailing whitespace
         run: "! git grep -EIn $'[ \t]+$'"
-  yamllint:
-    name: 🍶 YAML
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-        with:
-          python-version: '3.x'  # Version range or exact version of a Python version to use, using SemVer's version range syntax
-          architecture: 'x64'  # optional x64 or x86. Defaults to x64 if not specified
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip
-          pip install yamllint
-      - name: 🧹 YAML Lint
-        run: |
-          # return non-zero exit code on warnings
-          yamllint --strict .

.github/workflows/linter.yml

@@ -0,0 +1,25 @@
+name: Lint Code Base
+
+on:
+  push:
+    branches-ignore: [master]
+    # Remove the line above to run when pushing to master
+  pull_request:
+    branches: [master]
+
+jobs:
+  build:
+    name: Lint Code Base
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: github/super-linter@v3
+        env:
+          ERROR_ON_MISSING_EXEC_BIT: true
+          VALIDATE_BASH: true
+          # VALIDATE_BASH_EXEC: true
+          # VALIDATE_EDITORCONFIG: true
+          VALIDATE_MARKDOWN: true
+          # VALIDATE_SHELL_SHFMT: true
+          VALIDATE_YAML: true
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}