followup #17561, skipping ci now implies green (#17813)

* followup #17561, skip ci now implies green; [skip ci]
* fixup [skip ci]
* fixup test without skip ci
* fixup [skip ci]
* fixup2 [skip ci]
* github actions now automatically supports [skip ci]

.github/workflows/ci_docs.yml

@@ -30,9 +30,6 @@ on:
 
 jobs:
   build:
-    # see D20210329T004830
-    if: |
-      !contains(format('{0}', github.event.pull_request.title), '[skip ci]')
     strategy:
       fail-fast: false
       matrix:
@@ -54,14 +51,6 @@ jobs:
         with:
           fetch-depth: 2
 
-      - name: 'Check whether to skip CI'
-        shell: bash
-        run: |
-          # see D20210329T004830
-          commitMsg=$(git log --no-merges -1 --pretty=format:"%s")
-          echo commitMsg: $commitMsg
-          echo $commitMsg | grep -v '\[skip ci\]'
-
       - name: 'Install build dependencies (macOS)'
         if: runner.os == 'macOS'
         run: brew install make