feat(deps): adopt flatten plugin and google-cloud-shared-dependencies (#174)

Author: yangnuoyu

pom.xml

@@ -152,7 +152,6 @@
     <github.global.server>github</github.global.server>
     <site.installationModule>google-cloud-datastore-parent</site.installationModule>
     <project.javadoc.protobufBaseURL>https://googleapis.dev/java/google-api-grpc/latest</project.javadoc.protobufBaseURL>
-    <javax.annotations.version>1.3.2</javax.annotations.version>
   </properties>
 
   <dependencyManagement>

proto-google-cloud-datastore-v1/pom.xml

@@ -44,7 +44,6 @@
         <dependency>
           <groupId>javax.annotation</groupId>
           <artifactId>javax.annotation-api</artifactId>
-          <version>${javax.annotations.version}</version>
         </dependency>
       </dependencies>
     </profile>