add gitea workflows

.gitea/workflows/build.yaml

@@ -0,0 +1,25 @@
+name: build and publish
+
+on: push
+env:
+    DEV_SHELL_NAME: CI
+jobs:
+  check_config:
+    runs-on: flakes-action
+    steps:
+      - uses: actions/checkout@v3
+        name: Checkout
+      - name: Metadata
+        run: |
+          nix flake metadata
+      - name: Statix
+        run: |
+          nix develop -c statix check
+      - name: Flake check
+        run: |
+          nix flake check
+  build:
+    runs-on: flakes-action
+    steps:
+      - run: |
+          nix develop -c hugo --gc --minify