improve gha to parallelise building for multiple platforms

.github/workflows/build.yml

@@ -0,0 +1,46 @@
+name: Build Release
+on:
+  push:
+    tags: ["*"]
+    branches: ["*"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      CARGO_REGISTRIES_CRATES_IO_PROTOCOL: "sparse"
+    strategy:
+      matrix:
+        target: ["x86_64-unknown-linux-musl", "aarch64-unknown-linux-musl"]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: Swatinem/rust-cache@v2
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Install cross
+        run: |
+          cargo install cross --git https://github.com/cross-rs/cross
+
+      - name: Build project ${{ matrix.target }}
+        run: |
+          cross build --release --target ${{ matrix.target }}
+
+      - name: Upload build result
+        uses: actions/upload-artifact@v4
+        with:
+          path: target/release/${{ matrix.target }}/modrinth-downloader
+          name: modrinth-downloader-${{ matrix.target }}
+
+  release:
+    runs-on: ubuntu-latest
+    needs: build
+
+    permissions:
+      contents: write
+    steps:
+      - name: Download build results
+        uses: actions/download-artifact@v4
+      - uses: softprops/action-gh-release@v1
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          files: |
+            modrinth-downloader-*