Oxid 53 Reduce number of github actions instances (tock#16)

* tock-ci trigger updates

Update ci.yml

* trigger paths update

trigger covers all boards and chips

Update .github/workflows/ci.yml

Update .github/workflows/ci.yml

Co-Authored-By: Alexandru Radovici <alexandru.radovici@wyliodrin.com>

---------

Co-authored-by: Alexandru Radovici <alexandru.radovici@wyliodrin.com>

.github/workflows/ci.yml

@@ -7,9 +7,18 @@ env:
 # Controls when the action will run. Triggers the workflow on push or pull request
 # events but only for the master branch
 on:
-  push:
+  pull_request:
     branches-ignore: [ staging.tmp, trying.tmp ] # Run CI for all branches except bors tmp branches
-
+    paths:
+      - 'arch/**'
+      - 'boards/**'
+      - 'capsules/**'
+      - 'kernel/**'
+      - 'chips/**'
+      - 'libraries/**'
+  push:
+    branches:
+      - 'master'
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 # If you add additional jobs, remember to add them to bors.toml
 permissions: