Reduce code duplication

Use reusable workflows

.gitea/workflows/publish.yaml

@@ -0,0 +1,29 @@
+name: Publish diagram
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  render:
+    uses: ./.gitea/workflows/render.yaml
+
+  publish:
+    needs: render
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Download build artifact
+        uses: actions/download-artifact@v3
+        with:
+          name: polycule.png
+          path: ./
+      - name: Upload to cdn
+        uses: appleboy/scp-action@v0.1.7
+        with:
+          host: bruynooghe.dev
+          username: elizhium
+          password: ${{ secrets.ELIZHIUMPW }}
+          source: "polycule.*"
+          target: "/home/elizhium/CDN"