Bigtable: publish emulator to maven central (#4106)

* Bigtable: publish emulator to maven central

* make sure nexus plugin is not disabled

google-cloud-testing/google-cloud-bigtable-emulator/pom.xml

@@ -12,6 +12,17 @@
   <artifactId>google-cloud-bigtable-emulator</artifactId>
   <version>0.71.1-alpha-SNAPSHOT</version><!-- {x-version-update:google-cloud-bigtable-emulator:current} -->
 
+  <distributionManagement>
+    <snapshotRepository>
+      <id>sonatype-nexus-snapshots</id>
+      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+    </snapshotRepository>
+    <repository>
+      <id>sonatype-nexus-staging</id>
+      <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
+    </repository>
+  </distributionManagement>
+
   <build>
     <plugins>
       <plugin>
@@ -39,6 +50,19 @@
           </execution>
         </executions>
       </plugin>
+
+      <plugin>
+        <groupId>org.sonatype.plugins</groupId>
+        <artifactId>nexus-staging-maven-plugin</artifactId>
+        <version>1.6.6</version>
+        <extensions>true</extensions>
+        <configuration>
+          <serverId>ossrh</serverId>
+          <nexusUrl>https://oss.sonatype.org/</nexusUrl>
+          <autoReleaseAfterClose>false</autoReleaseAfterClose>
+          <skipNexusStagingDeployMojo>false</skipNexusStagingDeployMojo>
+        </configuration>
+      </plugin>
     </plugins>
   </build>