pom.xml: move compiler versions into properties

pom.xml

@@ -28,11 +28,13 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+
         <bitbucket.version>4.0.1</bitbucket.version>
         <bitbucket.data.version>${bitbucket.version}</bitbucket.data.version>
         <atlassian-sal-api.version>3.0.5</atlassian-sal-api.version>
-        <amps.version>6.1.0</amps.version>
-
+        <amps.version>6.3.0</amps.version>
     </properties>
 
     <dependencyManagement>
@@ -101,14 +103,6 @@
                     </products>
                 </configuration>
             </plugin>
-            <plugin>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.2</version>
-                <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
-                </configuration>
-            </plugin>
         </plugins>
     </build>