style: move push action to new dir so github and gitea can share it

.gitea/workflows/update.yaml

@@ -9,33 +9,21 @@ jobs:
   update:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout
-        uses: actions/checkout@v4
+      - uses: actions/checkout@v4
+      - uses: ./.actions/init
         with:
-          fetch-depth: 0
-
-      - name: Install Nix
-        uses: cachix/install-nix-action@v31
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-
-      - name: Use Cachix
-        uses: cachix/cachix-action@v16
-        with:
-          name: trevstack
-          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+          token: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
       # https://github.com/actions/checkout/issues/13
-      - name: Set Git Config
+      - name: Set git config
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
           git checkout -B update
 
-      - name: Update
-        run: nix run .#update
+      - run: nix run .#update
 
-      - name: Create Pull Request
+      - name: Create pull request
         env:
           PAT: ${{ secrets.PAT }}
         run: |