Change GitHub Action Triggers to all PR and Pushes to main

.github/workflows/black.yml

@@ -1,6 +1,10 @@
 name: "Black"
 
-on: [push]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 jobs:
   black:
     runs-on: ${{ matrix.os }}

.github/workflows/linters.yml

@@ -1,6 +1,10 @@
 name: "Linters"
 
-on: [push]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 jobs:
   pylint:
     name: Python Code Quality and Lint

.github/workflows/packaging_test.yml

@@ -1,6 +1,10 @@
 name: "Packaging Test"
 
-on: [push]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 jobs:
   coverage:
     runs-on: ${{ matrix.os }}

.github/workflows/unittests.yml

@@ -1,6 +1,9 @@
 name: "Unittests"
-
-on: [push]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
 jobs:
   pytest:
     runs-on: ${{ matrix.os }}