Refactor GitHub Actions workflow to limit triggers to the main branch

Author: coolbeevip

.github/workflows/pr.yml

@@ -2,20 +2,9 @@ name: CI
 
 on:
   push:
-    paths:
-      - "src/**"
-      - "*.py"
-      - "*.toml"
-      - "requirements.txt"
-      - ".github/workflows/**"
+    branches: [ "main" ]
   pull_request:
-    paths:
-      - "src/**"
-      - "*.py"
-      - "*.toml"
-      - "requirements.txt"
-      - ".github/workflows/**"
-
+    branches: [ "main" ]
 jobs:
   ruff:
     runs-on: ubuntu-latest