ci: add a workflow for release automation

Signed-off-by: Changyuan Lyu <changyuanl@google.com>

Author: Lencerf

.github/workflows/release.yml

@@ -0,0 +1,68 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build_alioth:
+    strategy:
+      matrix:
+        include:
+          - target: x86_64-unknown-linux-gnu
+            os: ubuntu-latest
+          - target: aarch64-unknown-linux-gnu
+            os: ubuntu-24.04-arm
+          - target: aarch64-apple-darwin
+            os: macos-latest
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Build
+        run: RUSTFLAGS='-C target-feature=+crt-static' cargo +stable build --target ${{ matrix.target }} --release
+      - name: Upload artifact
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        with:
+          name: alioth-${{ matrix.target }}
+          path: target/${{ matrix.target }}/release/alioth
+
+  build_bootloader:
+    uses: ./.github/workflows/bootloader.yml
+
+  create_release:
+    needs: [build_alioth, build_bootloader]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+      - name: Get tag message
+        id: tag_message
+        run: |
+          echo "msg<<EOF" >> "$GITHUB_OUTPUT"
+          git show -s --format=%b HEAD | head -n -2 \
+              >> "$GITHUB_OUTPUT"
+          echo "EOF" >> "$GITHUB_OUTPUT"
+      - name: Download all artifacts
+        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0
+        with:
+          path: artifacts
+      - name: Create tarballs
+        run: |
+          for dir in artifacts/alioth-*; do
+              IFS='-' read -r -a parts <<< "$dir"
+              arch=${parts[1]}
+              os=${parts[3]}
+              tar -cJf alioth-${os}-${arch}.tar.xz \
+                -C $PWD/$dir alioth \
+                -C $PWD/artifacts/kernel-${arch} kernel-${arch}
+          done
+      - name: Create Release
+        uses: softprops/action-gh-release@a06a81a03ee405af7f2048a818ed3f03bbf83c7b # v2.5.0
+        with:
+          files: alioth-*-*.tar.xz
+          fail_on_unmatched_files: true
+          draft: true
+          body: ${{ steps.tag_message.outputs.msg }}