feat(deps): adopt flatten plugin and google-cloud-shared-dependencies (#156)

Author: yangnuoyu

.gitignore

@@ -41,3 +41,5 @@ api_key
 *.pyc
 artman-genfiles
 venv
+
+.flattened-pom.xml

google-cloud-nio-examples/pom.xml

@@ -41,6 +41,10 @@
           <skip>true</skip>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>flatten-maven-plugin</artifactId>
+      </plugin>
     </plugins>
   </build>
 </project>

google-cloud-nio-retrofit/pom.xml

@@ -26,6 +26,10 @@
           <skip>false</skip>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>flatten-maven-plugin</artifactId>
+      </plugin>
     </plugins>
   </build>
 </project>

google-cloud-nio/pom.xml

@@ -183,6 +183,7 @@
           </ignoredUnusedDeclaredDependencies>
         </configuration>
       </plugin>
+      
     </plugins>
   </build>
 </project>

pom.xml

@@ -72,14 +72,18 @@
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <github.global.server>github</github.global.server>
     <site.installationModule>google-cloud-storage-nio-parent</site.installationModule>
-    <junit.version>4.13</junit.version>
-    <auto-value-annotations.version>1.7.3</auto-value-annotations.version>
-    <auto-value.version>1.7.3</auto-value.version>
-    <guava.version>29.0-android</guava.version>
   </properties>
 
   <dependencyManagement>
     <dependencies>
+      <dependency>
+        <groupId>com.google.cloud</groupId>
+        <artifactId>google-cloud-shared-dependencies</artifactId>
+        <version>0.8.1</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-storage</artifactId>
@@ -94,58 +98,18 @@
         <groupId>com.google.auto.value</groupId>
         <artifactId>auto-value</artifactId>
         <scope>provided</scope> <!-- to leave out of the all-deps jar -->
-        <version>${auto-value.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.google.protobuf</groupId>
-        <artifactId>protobuf-bom</artifactId>
-        <version>3.12.2</version>
-        <type>pom</type>
-        <scope>import</scope>
+        <version>${auto-value-annotation.version}</version>
       </dependency>
       <dependency>
        <groupId>com.google.auto.value</groupId>
         <artifactId>auto-value-annotations</artifactId>
-        <version>${auto-value-annotations.version}</version>
-      </dependency>
-      <dependency>
-        <groupId>com.google.cloud</groupId>
-        <artifactId>google-cloud-core-bom</artifactId>
-        <version>1.93.6</version>
-        <type>pom</type>
-        <scope>import</scope>
-      </dependency>
-      <dependency>
-        <groupId>com.google.api</groupId>
-        <artifactId>gax-bom</artifactId>
-        <version>1.57.0</version>
-        <type>pom</type>
-        <scope>import</scope>
-      </dependency>
-      <dependency>
-        <groupId>com.google.http-client</groupId>
-        <artifactId>google-http-client-bom</artifactId>
-        <version>1.35.0</version>
-        <type>pom</type>
-        <scope>import</scope>
-      </dependency>
-      <dependency>
-        <groupId>com.google.guava</groupId>
-        <artifactId>guava-bom</artifactId>
-        <version>${guava.version}</version>
-        <type>pom</type>
-        <scope>import</scope>
-      </dependency>
-      <dependency>
-        <groupId>com.google.code.findbugs</groupId>
-        <artifactId>jsr305</artifactId>
-        <version>3.0.2</version>
+        <version>${auto-value-annotation.version}</version>
       </dependency>
 
       <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
-        <version>${junit.version}</version>
+        <version>4.13</version>
         <scope>test</scope>
       </dependency>
       <dependency>
@@ -154,12 +118,6 @@
         <version>1.0.1</version>
         <scope>test</scope>
       </dependency>
-      <dependency>
-        <groupId>com.google.guava</groupId>
-        <artifactId>guava-testlib</artifactId>
-        <version>${guava.version}</version>
-        <scope>test</scope>
-      </dependency>
     </dependencies>
   </dependencyManagement>
   <build>