Include plugin version & use enforce plugin for Maven build stability
diff --git a/pom.xml b/pom.xml
index bfc6b3c..bb6a2aa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -175,7 +175,6 @@
             <plugin>
                 <groupId>org.jetbrains.dokka</groupId>
                 <artifactId>dokka-maven-plugin</artifactId>
-                <version>${dokka.version}</version>
                 <executions>
                     <execution>
                         <phase>pre-site</phase>
@@ -206,15 +205,58 @@
                     <skip>true</skip>
                 </configuration>
             </plugin>
+            <!-- enforcer -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-enforcer-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>enforce-versions</id>
+                        <goals>
+                            <goal>enforce</goal>
+                        </goals>
+                        <configuration>
+                            <rules>
+                                <requireJavaVersion>
+                                    <version>1.8.0</version>
+                                </requireJavaVersion>
+                                <requirePluginVersions>
+                                    <message>Always define plugin versions!</message>
+                                    <banLatest>true</banLatest>
+                                    <banRelease>true</banRelease>
+                                </requirePluginVersions>
+                            </rules>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
 
         <pluginManagement>
             <plugins>
+                <!-- Kotlin -->
                 <plugin>
                     <groupId>org.jetbrains.kotlin</groupId>
                     <artifactId>kotlin-maven-plugin</artifactId>
                     <version>${kotlin.version}</version>
                 </plugin>
+                <!-- Dokka -->
+                <plugin>
+                    <groupId>org.jetbrains.dokka</groupId>
+                    <artifactId>dokka-maven-plugin</artifactId>
+                    <version>${dokka.version}</version>
+                </plugin>
+                <!-- Maven -->
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-enforcer-plugin</artifactId>
+                    <version>3.0.0-M1</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-clean-plugin</artifactId>
+                    <version>2.5</version>
+                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-source-plugin</artifactId>
@@ -222,6 +264,11 @@
                 </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <version>2.4</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-release-plugin</artifactId>
                     <version>2.5.2</version>
                 </plugin>
@@ -240,6 +287,31 @@
                     <artifactId>maven-site-plugin</artifactId>
                     <version>3.3</version>
                 </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-jar-plugin</artifactId>
+                    <version>3.0.2</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-dependency-plugin</artifactId>
+                    <version>2.8</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.1</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-resources-plugin</artifactId>
+                    <version>2.6</version>
+                </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-antrun-plugin</artifactId>
+                    <version>1.3</version>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>