Build against gerrit-plugin-api 3.0.2

Update JGit dependency to 5.3.5.201909031855-r, which is the one used
in Gerrit 3.0.

Author: tomaswolf

docu/index.md

@@ -5,7 +5,7 @@ with full SSO through Gerrit.
 
 * License: [Apache Public License 2.0](http://www.apache.org/licenses/LICENSE-2.0)
 * [Home page](https://github.com/tomaswolf/gerrit-gitblit-plugin)
-* Installed plugin version: <em id='gerrit-gitblit-current-version'>2.16.171.2-SNAPSHOT</em> &mdash; <a id='gerrit-gitblit-version-check' style='display:none;' href='#'>Check for updates</a>
+* Installed plugin version: <em id='gerrit-gitblit-current-version'>3.0.171.0-SNAPSHOT</em> &mdash; <a id='gerrit-gitblit-version-check' style='display:none;' href='#'>Check for updates</a>
 
 For a list of contributors, see at [GitHub](https://github.com/tomaswolf/gerrit-gitblit-plugin/graphs/contributors).
 
@@ -92,6 +92,6 @@ Report bugs or make feature requests at the [GitHub issue tracker](https://githu
 
 <hr style="color: #C0C0C0; background-color: #C0C0C0; border-color: #C0C0C0; height: 2px;" />
 <div style="float:right;">
-<a href="https://github.com/tomaswolf/gerrit-gitblit-plugin" target="_blank">GitBlit plugin 2.16.171.2-SNAPSHOT</a>
+<a href="https://github.com/tomaswolf/gerrit-gitblit-plugin" target="_blank">GitBlit plugin 3.0.171.0-SNAPSHOT</a>
 </div>
 <script type="text/javascript" src="version_check.js"></script>

pom.xml

@@ -20,7 +20,7 @@ limitations under the License.
   <artifactId>gitblit-plugin</artifactId>
   <description>GitBlit for Gerrit integrated as a plugin</description>
   <name>Gerrit - GitBlit Plugin</name>
-  <version>2.16.171.2-SNAPSHOT</version><!-- Gerrit API version followed by collapsed GitBlit version, followed by plugin version -->
+  <version>3.0.171.0-SNAPSHOT</version><!-- Gerrit API version followed by collapsed GitBlit version, followed by plugin version -->
   <licenses>
     <license>
       <name>Apache License 2.0</name>
@@ -29,7 +29,8 @@ limitations under the License.
   </licenses>
   <properties>
     <Gerrit-ApiType>plugin</Gerrit-ApiType>
-    <Gerrit-ApiVersion>2.16.7</Gerrit-ApiVersion>
+    <Gerrit-ApiVersion>3.0.2</Gerrit-ApiVersion>
+    <JGit-Version>5.3.5.201909031855-r</JGit-Version>
     <GitBlit-Version>1.7.1</GitBlit-Version>
     <Wicket-Version>1.4.22</Wicket-Version>
     <Lucene-Version>6.6.5</Lucene-Version>
@@ -93,7 +94,7 @@ limitations under the License.
     <dependency>
       <groupId>org.eclipse.jgit</groupId>
       <artifactId>org.eclipse.jgit</artifactId>
-      <version>5.1.6.201903130242-r</version>
+      <version>${JGit-Version}</version>
     </dependency>
     <dependency>
       <groupId>com.google.gerrit</groupId>
@@ -187,7 +188,7 @@ limitations under the License.
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-shade-plugin</artifactId>
-        <version>2.3</version>
+        <version>2.4.3</version>
         <configuration>
           <promoteTransitiveDependencies>true</promoteTransitiveDependencies>
           <artifactSet>