Update actions/cache action

Author: netmindz

.github/workflows/wled-ci.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Cache pip
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
@@ -40,14 +40,14 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Cache pip
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
         restore-keys: |
           ${{ runner.os }}-pip-
     - name: Cache PlatformIO
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.platformio
         key: ${{ runner.os }}-${{ matrix.environment}}-${{ hashFiles('platformio.ini') }}