Github Actions: only on push to main (#1916)

.github/workflows/test_code.yml

@@ -1,6 +1,10 @@
 name: Code Tests
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 
 jobs:
   run:

.github/workflows/test_latest_branca.yml

@@ -1,6 +1,10 @@
 name: Code Tests with Latest branca
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 
 jobs:
   run:

.github/workflows/test_mypy.yml

@@ -1,6 +1,10 @@
 name: Mypy type hint checks
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 
 jobs:
   run:

.github/workflows/test_selenium.yml

@@ -1,6 +1,10 @@
 name: Selenium Tests
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 
 jobs:
   run: