update yaml (#6)

Co-authored-by: Artur Bać <[email protected]>

.github/workflows/cmake.yml

@@ -1,6 +1,16 @@
 name: CMake
 
-on: [push]
+on:
+  push:
+    branches: [ "master" ]
+    paths-ignore:
+      - 'README.md'
+      - 'docs/**'
+
+  pull_request:
+    paths-ignore:
+      - 'README.md'
+      - 'docs/**'
 
 env:
   # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)