actions/cache@v6 : remove absolute paths

.gitea/workflows/foxmesh-ci.yml

@@ -55,8 +55,7 @@ jobs:
         uses: actions/cache@v6
         with:
           path: |
-            ~/.cache/pio
+            .platformio
-            ~/.platformio
             .pio
           key: ${{ runner.os }}-pio-${{ hashFiles('**/platformio.ini') }}
             restore-keys: |