Update build.yml

Signed-off-by: Frédéric Metrich <45318189+FredM67@users.noreply.github.com>

.github/workflows/build.yml

@@ -22,14 +22,23 @@ jobs:
     - uses: actions/checkout@v4
       with:
         submodules: 'true'
+    - uses: actions/cache@v3
+      with:
+        path: |
+          ~/.cache/pip
+          ~/.platformio/.cache
+        key: ${{ runner.os }}-pio
     - name: Set up Python
       uses: actions/setup-python@v4
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install platformio
+    - name: Install PlatformIO Core
+      run: |
+        pip install --upgrade platformio
     # It is important to first install the libraries before compiling, since otherwise compilation might fail to find the just-installed libraries
     - name: Install platformIO libraries
       run: pio lib install
     - name: Run PlatformIO
-      run: platformio run
+      run: |
+        pio run --project-dir Mk2_3phase_RFdatalog_temp