chore: update GitHub Actions workflow for AUTHORS file

- Modified the update-authors.yml workflow to run only on a monthly schedule instead of on push to the main branch.
- Simplified the contributor filtering logic by changing the regex to exclude all bot accounts in a single line, enhancing maintainability.

These changes streamline the process of updating the AUTHORS file and improve the clarity of the workflow configuration.

.github/workflows/update-authors.yml

@@ -1,9 +1,7 @@
 name: Update AUTHORS file
 
 on:
-  # Run on push to main branch and monthly
-  push:
-    branches: [ main ]
+  # Run monthly
   schedule:
     - cron: '0 0 1 * *'  # Monthly
   workflow_dispatch:  # Manual trigger
@@ -28,8 +26,7 @@ jobs:
           # Fetch all contributors using GitHub CLI and filter out bots and owner
           contributors=$(gh api repos/tphakala/birdnet-go/contributors --jq '.[].login' | \
             grep -v "tphakala" | \
-            grep -v "dependabot\[bot\]" | \
-            grep -v "^bot-" | \
+            grep -v "\[bot\]" | \
             sort)
           
           # Create new AUTHORS file