Fixes for maven deploy (#366)

gradle-plugin-mvn-wrapper:
* Fix disabling of install and deploy
* Set skipNexusStagingDeployMojo to true

Author: jmini

modules/openapi-generator-gradle-plugin/pom.xml

@@ -13,6 +13,9 @@
     <name>openapi-generator-gradle-plugin (maven wrapper)</name>
     <description>This is a maven wrapper to call gradle during installation phase</description>
 
+    <properties>
+        <skipNexusStagingDeployMojo>true</skipNexusStagingDeployMojo>
+    </properties>
 
     <dependencies>
         <dependency>
@@ -23,19 +26,28 @@
     </dependencies>
 
     <build>
-        <plugins>
+        <!-- NOTE: Consider this temporary, as a way to cleanly hook into our pipeline.
+            We've discussed moving the entire project to gradle https://github.com/OpenAPITools/openapi-generator/issues/200, which would avoid this fitting. -->
+        <pluginManagement>
+            <plugins>
+                <!-- 1) disable maven install. This wrapper is not needed. (gradle will install a jar and a pom into the local maven repo) -->
+                <plugin>
+                    <artifactId>maven-install-plugin</artifactId>
+                    <configuration>
+                        <skip>true</skip>
+                    </configuration>
+                </plugin>
+                <!-- 3) disable maven deploy. This wrapper is not needed. -->
+                <plugin>
+                    <artifactId>maven-deploy-plugin</artifactId>
+                    <configuration>
+                        <skip>true</skip>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
 
-            <!-- NOTE: Consider this temporary, as a way to cleanly hook into our pipeline.
-                We've discussed moving the entire project to gradle https://github.com/OpenAPITools/openapi-generator/issues/200, which would avoid this fitting. -->
-            <!-- 1) disable maven install. This wrapper is not needed. (gradle will install a jar and a pom into the local maven repo) -->
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-install-plugin</artifactId>
-                <version>2.5.2</version>
-                <configuration>
-                    <skip>true</skip>
-                </configuration>
-            </plugin>
+        <plugins>
             <!-- 2) run gradle -->
             <plugin>
                 <groupId>org.fortasoft</groupId>
@@ -65,15 +77,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <!-- 3) disable maven deploy. This wrapper is not needed. -->
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-deploy-plugin</artifactId>
-                <version>2.8.2</version>
-                <configuration>
-                    <skip>true</skip>
-                </configuration>
-            </plugin>
         </plugins>
     </build>