Bump github/issue-metrics from 3.1.1 to 3.18.4

Bumps [github/issue-metrics](https://github.com/github/issue-metrics) from 3.1.1 to 3.18.4.
- [Release notes](https://github.com/github/issue-metrics/releases)
- [Commits](https://github.com/github/issue-metrics/compare/4f29f34d9d831fe224cbc6c8a0d711415ebd01b1...ed6e4b2b46f44ec7cdd2f6c145757a67a07ecf5b)

---
updated-dependencies:
- dependency-name: github/issue-metrics
  dependency-version: 3.18.4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/issue-metrics.yml

@@ -35,7 +35,7 @@ jobs:
         echo "last_month=$first_day..$last_day" >> "$GITHUB_ENV"
 
     - name: Run issue-metrics tool
-      uses: github/issue-metrics@4f29f34d9d831fe224cbc6c8a0d711415ebd01b1 # v3.1.1
+      uses: github/issue-metrics@ed6e4b2b46f44ec7cdd2f6c145757a67a07ecf5b # v3.18.4
       env:
         GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         SEARCH_QUERY: 'repo:FreeCAD/FreeCAD is:issue created:${{ env.last_month }}'