Upgrade to latest actions versions

We need to use the latest versions because older nodejs runtimes have
been deprecated and removed some time ago.

As a bonus, the latest version of the setup-python action supports
caching pip dependencies out-of-the-box (setting the appropriate cache
option) so we can eliminate a few of the manual steps to setup
dependency caching.

Finally, I also bumped the python version to 3.13 which is what
currently ships in the Arch repositories, not that it really matters.

.github/workflows/galaxy.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout git repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v5
         with:
           path: collections/ansible_collections/kewlfft/aur
 
@@ -26,22 +26,10 @@ jobs:
           echo ::set-output name=version::$(awk -F '/' '{print substr($3, 2)}' <<< ${GITHUB_REF})
 
       - name: "Set up Python"
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
-
-      - name: Generate cache keys
-        id: keys
-        run: |
-          echo ::set-output name=pip_cache_dir::$(pip cache dir)
-          # This ensures that the cache is invalidated after a week
-          echo ::set-output name=date::$(date +%Y_%g)
-
-      - name: Pip Cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.keys.outputs.pip_cache_dir }}
-          key: ansible-pip-${{ steps.keys.outputs.date }}
+          python-version: "3.13"
+          cache: 'pip'
 
       - name: Install pip packages
         run: |