chore(CI): add env var JAVA_TOOL_OPTIONS, hack/unify os properties

- environment variables are visible to child processes
- set env var `JAVA_TOOL_OPTIONS` to `-Dfile.encoding=UTF-8 -Duser.timezone=Asia/Shanghai`

.github/workflows/ci.yaml

@@ -33,6 +33,8 @@ jobs:
           cache: maven
       - name: Build with Maven and generate code coverage
         run: ./mvnw -V --no-transfer-progress -Pgen-javadoc -Pgen-dokka clean package
+        env:
+          JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF-8 -Duser.timezone=Asia/Shanghai
       # https://github.com/marketplace/actions/codecov
       - uses: codecov/codecov-action@v3
         with: