Upgrade with the Gradle Wrapper, gradlew升级

springboot 2.0需要gradle 1+, 而自动构建的都是3.+，手动升级如下

Upgrade with the Gradle Wrapper

If your existing Gradle-based build uses the Gradle Wrapper, you can easily upgrade by running the wrapper task, specifying the desired Gradle version:

$ ./gradlew wrapper --gradle-version=4.3.1 --distribution-type=bin

Note that it is not necessary for Gradle to be installed to use the Gradle wrapper. The next invocation of gradlew or gradlew.bat will download and cache the specified version of Gradle.

$ ./gradlew tasks
Downloading https://services.gradle.org/distributions/gradle-4.3.1-bin.zip