add demo workflow

.gitea/workflows/build-and-test.yaml

@@ -0,0 +1,26 @@
+name: Build & Test
+run-name: Build & Test
+on: [push, pull_request]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Rust
+        id: rust-toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Cache build artifacts
+        uses: actions/cache@v3
+        with:
+          key: ${{ runner.os }}-cargo-${{ steps.rust-toolchain.outputs.cachekey }}-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-cargo-${{ steps.rust-toolchain.outputs.cachekey }}-
+          path: |
+            **/target
+
+      - name: Build
+        run: cargo build
+      - name: Test
+        run: cargo test