workflows/os_comp: Don't run if there aren't relavent changes

.github/workflows/os_comp.yml

@@ -6,7 +6,19 @@ on:
       - master
       # Stable branches such as 0.56 or the eventual 1.0
       - '[0-9]+.[0-9]+'
+    paths:
+      - "mesonbuild/**"
+      - "test cases/**"
+      - ".github/workflows/images.yml"
+      - ".github/workflows/os_comp.yml"
+      - "run_unittests.py"
   pull_request:
+    paths:
+      - "mesonbuild/**"
+      - "test cases/**"
+      - ".github/workflows/images.yml"
+      - ".github/workflows/os_comp.yml"
+      - "run_unittests.py"
 
 jobs:
   arch: