Resolve revision property in POMs (#268)

The `revision` property is used to consolidate the configuration of the
modules' versions.  Since we want to deploy these artifacts, that
property must be resolved in order for Maven to find the parents later.

See [Maven CI Friendly Versions][1]

[1]: https://maven.apache.org/maven-ci-friendly.html

Reviewer: giacomo.calmasini

.gitignore

@@ -1,4 +1,6 @@
 .bundle
+# Created by flatten-maven-plugin
+.flattened-pom.xml
 build
 src/java/com/rapleaf/jack/util/MysqlFlex.java
 *.iml

pom.xml

@@ -85,6 +85,31 @@
         </configuration>
       </plugin>
 
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>flatten-maven-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>flatten</id>
+            <phase>process-resources</phase>
+            <goals>
+              <goal>flatten</goal>
+            </goals>
+            <configuration>
+              <updatePomFile>true</updatePomFile>
+              <flattenMode>resolveCiFriendliesOnly</flattenMode>
+            </configuration>
+          </execution>
+          <execution>
+            <id>flatten.clean</id>
+            <phase>clean</phase>
+            <goals>
+              <goal>clean</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+
     </plugins>
 
     <pluginManagement>
@@ -99,6 +124,11 @@
           <artifactId>maven-surefire-plugin</artifactId>
           <version>2.22.2</version>
         </plugin>
+        <plugin>
+          <groupId>org.codehaus.mojo</groupId>
+          <artifactId>flatten-maven-plugin</artifactId>
+          <version>1.2.2</version>
+        </plugin>
       </plugins>
     </pluginManagement>
   </build>