Adjust CI workflow for flat library layout

This is one of the few official libraries that still uses the old "flat layout", but the CI workflow was configured for the modern "recursive layout.

Author: per1234

.github/workflows/compile-examples.yml

@@ -6,12 +6,18 @@ on:
     paths:
       - ".github/workflows/compile-examples.yml"
       - "examples/**"
-      - "src/**"
+      - "**.c"
+      - "**.cpp"
+      - "**.h"
+      - "*.S"
   pull_request:
     paths:
       - ".github/workflows/compile-examples.yml"
       - "examples/**"
-      - "src/**"
+      - "**.c"
+      - "**.cpp"
+      - "**.h"
+      - "*.S"
   schedule:
     # Run every Tuesday at 8 AM UTC to catch breakage caused by changes to external resources (libraries, platforms).
     - cron: "0 8 * * TUE"