CI: skip some more builds when possible

When a commit only contains tests, documentation, or cmake files, skip
those builds that aren't affected by those.

The file filters available on the CI services don't seem to allow
skipping individual jobs, only the entire workflow, so we can't get any
more fine-grained than this.

.github/workflows/fuzz.yml

@@ -11,25 +11,31 @@ on:
     - '*/ci'
     paths-ignore:
     - '**/*.md'
+    - '**/CMakeLists.txt'
     - '.azure-pipelines.yml'
     - '.circleci/**'
     - '.cirrus.yml'
     - 'appveyor.yml'
+    - 'CMake/**'
     - 'packages/**'
     - 'plan9/**'
     - 'projects/**'
+    - 'tests/data/**'
     - 'winbuild/**'
   pull_request:
     branches:
     - master
     paths-ignore:
     - '**/*.md'
+    - '**/CMakeLists.txt'
     - '.azure-pipelines.yml'
     - '.cirrus.yml'
     - 'appveyor.yml'
+    - 'CMake/**'
     - 'packages/**'
     - 'plan9/**'
     - 'projects/**'
+    - 'tests/data/**'
     - 'winbuild/**'
 
 concurrency: