deps: update docker/login-action action to v4

Reviewed-on: #5

.gitea/workflows/build.yml

@@ -18,10 +18,10 @@ jobs:
         - /var/run/docker.sock:/var/run/docker.sock
     steps:
       - uses: actions/checkout@v7
-      - uses: docker/login-action@v3
+      - uses: docker/login-action@v4
         with:
           registry: git.studiovita.li
-          username: ${{ gitea.actor }}
+          username: ${{ secrets.REGISTRY_USERNAME }}
           password: ${{ secrets.REGISTRY_TOKEN }}
       - uses: docker/build-push-action@v6
         with:

README.md

@@ -0,0 +1,31 @@
+# studiovitali/actions
+
+Shared Gitea Actions for studio CI workflows.
+
+## Composite actions
+
+- **[`sops`](sops/)** — install checksum-verified SOPS and decrypt `*.sops.*` files with an age key
+- **[`ssh-copy`](ssh-copy/)** — `rsync` a local directory to a remote host over SSH
+- **[`ssh-run`](ssh-run/)** — run a script on a remote host over SSH
+
+Reference a local action from a workflow:
+
+```yaml
+- uses: studio/actions/ssh-run@main
+  with:
+    host: ${{ secrets.HOST }}
+    user: deploy
+    key: ${{ secrets.SSH_KEY }}
+    script: ./deploy.sh
+```
+
+## Runner image
+
+`images/act` builds `git.studiovita.li/studio/actions:ubuntu-latest` from the Gitea
+runner image, adding `rsync` and SOPS. Built weekly and on `images/**` changes via
+[`.gitea/workflows/build.yml`](.gitea/workflows/build.yml).
+
+## Maintenance
+
+Dependencies pinned in `action.yml` / `Dockerfile` are updated by [Renovate](renovate.json)
+using `## renovate:` annotations.

backup/action.yml

@@ -1,13 +0,0 @@
-name: backup
-description: backup all postgres databases
-
-runs:
-  using: "composite"
-  steps:
-    - name: dump databases
-      shell: bash
-      run: |
-        docker ps
-
-    # - name: backup databases
-    #   run: |