GHA: Do not trigger build for changes in non-code files.

* .github/workflows/linux-cmake.yml,
  .github/workflows/windows-cmake.yml
  (path-ignore): Add SConstruct

* .github/workflows/linux-old-scons.yml
  .github/workflows/linux.yml
  (path-ignore): Add CMakeLists.txt

* All above
  (path-ignore): Add CHANGES, LICENSE, NOTICE, README and design.guide.txt

Inspired by: r1935797 in Subversion by Ivan


git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1935809 13f79535-47bb-0310-9956-ffa450edef68
4 files changed