Migrate from woodpecker to forgejo actions

.forgejo/workflows/build.yaml

@@ -0,0 +1,16 @@
+on: [push]
+jobs:
+  build_image:
+    runs-on: docker
+    steps:
+      - name: Build and push image
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          tags: git.korhonen.cc/functionalhacker/forgejo-asciidoc
+      - name: Login to Docker registry (forgejo)
+        uses: docker/login-action@v3
+        with:
+          registry: git.korhonen.cc
+          username: ${{ secrets.REGISTRY_USER }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}

.woodpecker.yml

@@ -1,11 +0,0 @@
-steps:
-  build:
-    image: woodpeckerci/plugin-docker-buildx
-    settings:
-      repo: git.korhonen.cc/functionalhacker/forgejo-asciidoc
-      registry: https://git.korhonen.cc
-      username: FunctionalHacker
-      password:
-        from_secret: registry_password
-      tags: latest
-      platforms: linux/amd64