Add pico-sdk github workflow

.github/workflows/pc_debug_clang.yaml

@@ -23,4 +23,4 @@ jobs:
     - name: Compile
       run: |
         cd tools/pc_debug
-        CC=clang make
+        CC=clang make -j

.github/workflows/pico-sdk-cmake.yaml

@@ -0,0 +1,52 @@
+name: Build with Pico SDK develop
+
+on:
+  push:
+    branches: [ main, develop ]
+  pull_request:
+    branches: [ main, develop ]
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+
+    - name: Checkout pico-sdk/develop
+      uses: actions/checkout@v2
+      with:
+        repository: raspberrypi/pico-sdk
+        ref: develop
+        path: pico-sdk
+
+    - name: Checkout pico-sdk submodules
+      working-directory: ${{github.workspace}}/pico-sdk
+      run: git submodule update --init
+
+    - name: Configure CMake
+      # Use a bash shell so we can use the same syntax for environment variable
+      # access regardless of the host operating system
+      shell: bash
+      working-directory: ${{github.workspace}}/tools/pico_w/build
+      # Note the current convention is to use the -S and -B options here to specify source
+      # and build directories, but this is only available with CMake 3.13 and higher.
+      # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
+      run: PICO_SDK_PATH=../../pico-sdk cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DPICO_BOARD=pico_w
+
+    - name: Get core count
+      id: core_count
+      run : cat /proc/cpuinfo  | grep processor | wc -l
+
+    - name: Build
+      working-directory: ${{github.workspace}}/tools/pico_w/build
+      shell: bash
+      # Execute the build.  You can specify a specific target with "--target <NAME>"
+      run: cmake --build . --config $BUILD_TYPE --parallel $(nproc)