Correct variables for release

Author: mxdrenthe

pom.xml

@@ -47,6 +47,7 @@
   </developers>
 
   <properties>
+    <maven.plugin.release>3.1.1</maven.plugin.release>
     <el-api.version>5.0.0</el-api.version>
   </properties>
 
@@ -100,26 +101,26 @@
     <dependency>
       <groupId>org.onehippo.cms7.hst</groupId>
       <artifactId>hst-commons</artifactId>
-      <version>${parent.version}</version>
+      <version>${project.parent.version}</version>
     </dependency>
 
     <dependency>
       <groupId>org.onehippo.cms7.hst</groupId>
       <artifactId>hst-api</artifactId>
-      <version>${parent.version}</version>
+      <version>${project.parent.version}</version>
     </dependency>
 
     <dependency>
       <groupId>org.onehippo.cms7</groupId>
       <artifactId>hippo-cms7-commons</artifactId>
-      <version>${parent.version}</version>
+      <version>${project.parent.version}</version>
       <scope>test</scope>
     </dependency>
 
     <dependency>
       <groupId>org.onehippo.cms7</groupId>
       <artifactId>hippo-services</artifactId>
-      <version>${parent.version}</version>
+      <version>${project.parent.version}</version>
       <scope>test</scope>
     </dependency>