add release infra (#6)

.github/workflows/release.yml

@@ -0,0 +1,30 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+          distribution: 'adopt'
+      - name: Build GraalVM Native Image
+        uses: eskatos/gradle-command-action@v1.3.3
+        with:
+          arguments: nativeImage
+          wrapper-cache-enabled: true
+          dependencies-cache-enabled: true
+          configuration-cache-enabled: true
+      - name: Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: build/graal/klisp
+          draft: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}