build(ci): add buildjet arm runner

.github/workflows/main.yml

@@ -89,11 +89,40 @@ jobs:
         if: (github.ref_name == 'main' || startsWith(github.ref, 'refs/tags/dsp-meta-cmd'))
         run: just docker-push-arm64
 
+  # Build, test for arm64
+  build_arm64_buildjet:
+    runs-on: buildjet-8vcpu-ubuntu-2204-arm
+    concurrency:
+      group: ${{ github.ref }}-buildjet-arm64
+      cancel-in-progress: true
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # gets additionally all tags which we need
+      - uses: extractions/setup-just@v1
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          cache: false
+          components: rustfmt
+      - uses: buildjet/cache@v3
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            target/
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - run: just check
+      - run: just build
+      - run: just test
+
+
   # publish manifest combining aarch64 and amd64 images
   publish_manifest:
     name: Build and Publish Manifest to Dockerhub
     runs-on: ubuntu-latest
-    needs: [build_amd64, build_arm64]
+    needs: [ build_amd64, build_arm64 ]
     if: (github.ref_name == 'main' || startsWith(github.ref, 'refs/tags/dsp-meta-cmd'))
     outputs:
       tag: ${{ steps.output_docker_image_tag.outputs.tag }}