就是执行这一步报错，错误信息如下
[ERROR] Failed to execute goal org.codehaus.mojo:versions-maven-plugin:2.7:set (default-cli) on project ambari-metrics: Execution default-cli of goal org.codehaus.mojo:versions-maven-plugin:2.7:set failed: Plugin org.codehaus.mojo:versions-maven-plugin:2.7 or one of its dependencies could not be resolved: Failed to collect dependencies at org.codehaus.mojo:versions-maven-plugin:jar:2.7 -> org.apache.maven:maven-artifact:jar:2.2.1: Failed to read artifact descriptor for org.apache.maven:maven-artifact:jar:2.2.1: Could not transfer artifact org.apache.maven:maven-artifact:pom:2.2.1 from/to central (https://repo.maven.apache.org/maven2): Connect to repo.maven.apache.org:443 [repo.maven.apache.org/151.101.24.215] failed: 拒绝连接 (Connection refused) -> [Help 1]
打开下边help1 那个网址大概意思就是jar包的问题，或者是网络的问题。于是我找到了mavenjar包下载位置，找到了标绿的那个地方
删除了整个version-maven-plugin文件夹，然后再次执行mvn versions:set -DnewVersion=2.7.3.0.0，成功！
