Add dependabot.yml for Github Actions updates

And save it some work and update Actions to latest versions.

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+# Before applying suggested PRs, make sure that the new versions of any
+# updated actions are allowed in
+# https://github.com/organizations/geany/settings/actions
+# Versions are pinned and restricted for security reasons.
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/docker.yml

@@ -32,10 +32,10 @@ jobs:
 
     steps:
       - name: Checkout Build Scripts
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Log In To The Container Registry
-        uses: docker/login-action@v2
+        uses: docker/login-action@v3
         with:
           registry: ${{ env.DOCKER_REGISTRY }}
           username: ${{ github.actor }}

.github/workflows/package-cleanup.yml

@@ -22,7 +22,7 @@ jobs:
       DOCKER_IMAGE_NAME:    "geany-mingw64-ci"
 
     steps:
-      - uses: actions/delete-package-versions@v4
+      - uses: actions/delete-package-versions@v5
         with:
           package-name: ${{ env.DOCKER_IMAGE_NAME }}
           package-type: 'container'