ci: Build for 'arm64' and 'armhf' (#285)

* Build for 'arm64' and 'armhf'

* Add `armv7` support

Co-authored-by: Chuckame <Chuckame@users.noreply.github.com>

---------

Co-authored-by: Chuckame <Chuckame@users.noreply.github.com>

.github/workflows/release.yml

@@ -164,6 +164,7 @@ jobs:
         uses: docker/build-push-action@v2
         with:
           push: true
+          platforms: linux/amd64, linux/arm64, linux/armhf, linux/armv7
           tags: rapiz1/rathole:latest, rapiz1/rathole:${{ github.ref_name }}
   publish-crate:
     name: Publish to crates.io