Ensure no snapshots get referenced in release builds

[resolves #299]

Author: mp911de

pom.xml

@@ -292,6 +292,27 @@
                 <artifactId>maven-deploy-plugin</artifactId>
                 <version>2.8.2</version>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-enforcer-plugin</artifactId>
+                <version>3.0.0-M3</version>
+                <executions>
+                    <execution>
+                        <id>enforce-no-snapshots</id>
+                        <goals>
+                            <goal>enforce</goal>
+                        </goals>
+                        <configuration>
+                            <rules>
+                                <requireReleaseDeps>
+                                    <onlyWhenRelease>true</onlyWhenRelease>
+                                    <message>No Snapshots in releases allowed!</message>
+                                </requireReleaseDeps>
+                            </rules>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>