Run CI on push master or PR master

.github/workflows/ci-workflow.yml

@@ -1,6 +1,12 @@
 name: Compilation & tests
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
 
 jobs:
   job_build_debug:

.github/workflows/e2e-tests.yml

@@ -1,6 +1,12 @@
 name: End-to-end tests
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
 
 jobs:
   test_zemu:

.github/workflows/lint-workflow.yml

@@ -1,6 +1,12 @@
 name: Code style check
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
 
 jobs:
   job_lint: