chore fix: ccache missing

Author: Charliechen114514

.github/workflows/build-examples.yml

@@ -43,10 +43,9 @@ jobs:
 
       - name: Build host examples
         run: |
-          mkdir -p ~/.cache/ccache
+          export CCACHE_DIR="$HOME/.cache/ccache"
+          mkdir -p "$CCACHE_DIR"
           python3 scripts/build_examples.py --host
-        env:
-          CCACHE_DIR: ~/.cache/ccache
 
   build-stm32:
     name: STM32 Examples
@@ -73,7 +72,6 @@ jobs:
 
       - name: Build STM32 examples
         run: |
-          mkdir -p ~/.cache/ccache
+          export CCACHE_DIR="$HOME/.cache/ccache"
+          mkdir -p "$CCACHE_DIR"
           python3 scripts/build_examples.py --stm32
-        env:
-          CCACHE_DIR: ~/.cache/ccache