Add build workflow

.github/workflows/build.yml

@@ -0,0 +1,38 @@
+name: Build
+on:
+  push:
+    branches: [naive]
+    paths-ignore: [README.md]
+  release:
+    types: [published]
+defaults:
+  run:
+    shell: bash
+jobs:
+  build_caddy_with_naive:
+    runs-on: ubuntu-22.04
+    env:
+      BUNDLE: caddy-forwardproxy-naive
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ^1.21.9
+      - run: go install github.com/caddyserver/xcaddy/cmd/xcaddy@latest
+      - run: ~/go/bin/xcaddy build --with github.com/caddyserver/forwardproxy@master=$PWD
+      - name: Pack naiveproxy assets
+        run: |
+          mkdir ${{ env.BUNDLE }}
+          cp caddy LICENSE README.md ${{ env.BUNDLE }}
+          tar cJf ${{ env.BUNDLE }}.tar.xz ${{ env.BUNDLE }}
+          openssl sha256 ./caddy >sha256sum.txt
+          echo "SHA256SUM=$(cut -d' ' -f2 sha256sum.txt)" >>$GITHUB_ENV
+      - uses: actions/upload-artifact@v4
+        with:
+          name: ${{ env.BUNDLE }}.tar.xz caddy executable sha256 ${{ env.SHA256SUM }}
+          path: sha256sum.txt
+      - name: Upload caddy assets
+        if: ${{ github.event_name == 'release' }}
+        run: gh release upload "${GITHUB_REF##*/}"  ${{ env.BUNDLE }}.tar.xz --clobber
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}