Use more parallelism in CI

this decreases the total wait time, even if it uses more resources in all

.github/workflows/githubci.yml

@@ -4,6 +4,10 @@ on: [pull_request, push, repository_dispatch]
 
 jobs:
   build:
+    strategy:
+      matrix:
+        arduino-platform: ["feather_rp2350", "metro_rp2350"]
+
     runs-on: ubuntu-latest
 
     steps:
@@ -20,10 +24,41 @@ jobs:
       run: bash ci/actions_install.sh
 
     - name: test platforms
-      run: python3 ci/build_platform.py feather_rp2350 feather_rp2350_tinyusb metro_rp2350 metro_rp2350_tinyusb
+      run: python3 ci/build_platform.py ${{ matrix.arduino-platform }}
 
+  clang:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/setup-python@v4
+      with:
+        python-version: '3.x'
+    - uses: actions/checkout@v3
+    - uses: actions/checkout@v3
+      with:
+         repository: adafruit/ci-arduino
+         path: ci
+
+    - name: pre-install
+      run: bash ci/actions_install.sh
     - name: clang
-      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r .
+      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -e "./src/drivers/dvhstx" -e './.git' -r .
+
+  doxygen:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/setup-python@v4
+      with:
+        python-version: '3.x'
+    - uses: actions/checkout@v3
+    - uses: actions/checkout@v3
+      with:
+         repository: adafruit/ci-arduino
+         path: ci
+
+    - name: pre-install
+      run: bash ci/actions_install.sh
 
     - name: doxygen
       env: