chore: update Dependabot configuration to include additional labels for GitHub Actions (#24)

## Description

This pull request makes a small configuration update to Dependabot. The
change adds default labels to pull requests created for GitHub Actions
updates, making it easier to identify and filter these dependency PRs.

* Added the `dependencies` and `github-actions` labels to Dependabot PRs
for GitHub Actions updates in `.github/dependabot.yml`.

Author: MariusStorhaug

.github/dependabot.yml

@@ -7,5 +7,8 @@ version: 2
 updates:
   - package-ecosystem: github-actions # See documentation for possible values
     directory: / # Location of package manifests
+    labels:
+      - dependencies
+      - github-actions
     schedule:
       interval: weekly