Cleanup yaml formatting (#5151)

* Add yamllint config.
* Add yamllint workflow.
* Cleanup linting issues.
* Remove unnecessary `set -x -e` from workflows.

Signed-off-by: SuperQ <superq@gmail.com>

.github/workflows/make.doc.yml

@@ -8,31 +8,29 @@ jobs:
   fix:
     runs-on: ubuntu-latest
     steps:
-      -
-        name: Checkout
+      - name: Checkout
         uses: actions/checkout@v2
-      -
-        name: Setup Go
+
+      - name: Setup Go
         uses: actions/setup-go@v2
         with:
           go-version: '1.17.0'
-      -
-        name: Update Docs
+
+      - name: Update Docs
         run: |
           bash -x -e ./.github/fixup_file_mtime.sh
           make -f Makefile.doc
-      -
-        name: Set up Git
+
+      - name: Set up Git
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           git config user.name "coredns[bot]"
           git config user.email "bot@bot.coredns.io"
           git remote set-url origin https://x-access-token:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git
-      -
-        name: Commit and push changes
+
+      - name: Commit and push changes
         run: |
-          set -x -e
           git add .
           if output=$(git status --porcelain) && [ ! -z "$output" ]; then
             git commit -s -m 'auto make -f Makefile.doc'