Use development version of PlatformIO (MarlinFirmware#18724)

Author: ivankravets

.github/workflows/test-builds.yml

@@ -105,7 +105,7 @@ jobs:
 
     - name: Install PlatformIO
       run: |
-        pip install -U https://github.com/platformio/platformio-core/archive/master.zip
+        pip install -U https://github.com/platformio/platformio-core/archive/develop.zip
         platformio update
 
     - name: Check out the PR