Update to v5 and gitea actions (#1)

Reviewed-on: #1
Co-authored-by: Stanislav N. aka pztrn <pztrn@pztrn.name>
Co-committed-by: Stanislav N. aka pztrn <pztrn@pztrn.name>

.gitea/workflows/on-tag.yaml

@@ -0,0 +1,27 @@
+---
+name: "Build container"
+run-name: "Build container"
+on:
+  push:
+    tags:
+      - "**"
+
+jobs:
+  BuildImage:
+    runs-on: "ubuntu-22.04"
+    steps:
+      - name: "checkout source"
+        uses: actions/checkout@v4
+      - name: Login to Docker Registry
+        uses: docker/login-action@v3
+        with:
+          registry: code.pztrn.name
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+      - name: Build and push image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          platforms: linux/amd64
+          tags: code.pztrn.name/containers/go-toolbox:${{ gitea.ref_name }}