ci(workflows): 更新构建工作流中的密钥库路径引用

- 使用 github.workspace 变量替换硬编码路径
- 确保密钥库文件路径在不同环境中的一致性
- 提高工作流配置的可维护性和可靠性

Signed-off-by: Jesse205 <2055675594@qq.com>

Author: Jesse205

.github/workflows/build.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Decode Keystore
         run: |
           mkdir -p app/keystores
-          echo "${{ secrets.KEYSTORE_FILE }}" | base64 -d > app/keystores/keystore.jks
+          echo "${{ secrets.KEYSTORE_FILE }}" | base64 -d > ${{ github.workspace }}/app/keystores/keystore.jks
           chmod 600 app/keystores/keystore.jks
 
       - name: Grant execute permission for gradlew
@@ -39,7 +39,7 @@ jobs:
       - name: Build APK
         run: ./gradlew assembleRelease --stacktrace
         env:
-          KEYSTORE_FILE: app/keystores/keystore.jks
+          KEYSTORE_FILE: ${{ github.workspace }}/app/keystores/keystore.jks
           KEYSTORE_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
           KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
           KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}