[NIT-4309] CI: Create changelog fragment for dependabot PRs (#4219)

* Changelog

* New workflow

* Let's try it for this PR firstly

* Add a changelog entry for dependabot update

* Seems like it's working. Restoring the author filter then

* Remove the added changelog fragment

---------

Co-authored-by: Pepper Lebeck-Jobe <[email protected]>

Author: pmikolajczyk41

.github/workflows/automated-changelog.yml

@@ -0,0 +1,45 @@
+name: Changelog fragments for automated PRs
+
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  add-changelog:
+    # Only run if the PR is opened by dependabot
+    if: github.actor == 'dependabot[bot]'
+    runs-on: ubuntu-4
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v6
+
+      - name: Create Changelog File
+        uses: actions/github-script@v8
+        with:
+          script: |
+            const fs = require('fs');
+            const path = require('path');
+            
+            const dir = 'changelog';
+            
+            // Find the next available number
+            let x = 1;
+            while (fs.existsSync(path.join(dir, `dependabot-${x}.md`))) {
+              x++;
+            }
+
+            const filename = path.join(dir, `dependabot-${x}.md`);
+            const title = context.payload.pull_request.title;
+            const content = `### Ignored\n- ${title}\n`;
+
+            fs.writeFileSync(filename, content);
+            console.log(`Created ${filename} for PR: ${title}`);
+
+      - name: Commit and Push
+        uses: stefanzweifel/git-auto-commit-action@v7
+        with:
+          commit_message: "Add a changelog entry for dependabot update"
+          file_pattern: 'changelog/dependabot-*.md'

changelog/pmikolajczyk-nit-4309.md

@@ -0,0 +1,2 @@
+### Ignored
+- Automatically create changelog fragment for dependabot PRs