Update GH actions (#439)

.github/workflows/pyinstaller.yml

@@ -3,8 +3,6 @@ name: Package exe with PyInstaller - Windows
 on:
   push:
     branches: [ main ]
-  pull_request:
-    branches: [ main ]
 
 jobs:
   build:

.github/workflows/python-package.yml

@@ -2,6 +2,7 @@ name: Linting and testing
 
 on:
   push:
+    branches: [ main ]
   pull_request:
     branches: [ main ]
     types: [opened, synchronize, reopened]