ci: test on pico-sdk 1.5.1

also speed up CI tests by building only the hello_world/usb example

Author: urish

.github/workflows/ci-pico-sdk.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        sdk_version: [1.2.0, 1.3.1, 1.4.0]
+        sdk_version: [1.2.0, 1.3.1, 1.4.0, 1.5.1]
     steps:
       - uses: actions/checkout@v4
       - name: Cache Pico SDK
@@ -31,7 +31,7 @@ jobs:
           git clone https://github.com/raspberrypi/pico-sdk.git --depth 1 --branch ${SDK_VERSION}
           cd pico-sdk && git submodule update --init && cd ..
           git clone https://github.com/raspberrypi/pico-examples.git --depth 1 --branch "sdk-${SDK_VERSION}"
-          cd pico-examples && mkdir build && cd build && cmake .. && make -j4
+          cd pico-examples && mkdir build && cd build && cmake .. && make -C hello_world/usb -j4
         env:
           SDK_VERSION: ${{ matrix.sdk_version }}
           PICO_SDK_PATH: ~/pico/pico-sdk