Merge r1933654, r1934209, r1935338 from trunk: [CTR for CI changes]

Merge r1933654, r1934209, r1935338 from trunk: [CTR for CI changes]

CI: Fail early if PHP_FPM is set but not valid.
CI: Set PHP_FPM correctly for current Ubuntu images.

CI: Add *.md to the ignore list. (the "**" syntax is correct
here, per https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#filter-pattern-cheat-sheet)

CI: Skip Windows workflow for *.md changes.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1935340 13f79535-47bb-0310-9956-ffa450edef68