Define maven central with https (#11994)

pom.xml

@@ -52,8 +52,25 @@
         <phantomjs.version>2.1.1</phantomjs.version>
     </properties>
 
+    <repositories>
+        <repository>
+            <id>central</id>
+            <url>https://repo.maven.apache.org/maven2/</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </repository>
+    </repositories>
+    
     <!-- TODO: remove this after maven plugin has been released -->
     <pluginRepositories>
+        <pluginRepository>
+            <id>central</id>
+            <url>https://repo.maven.apache.org/maven2/</url>
+            <snapshots>
+                <enabled>false</enabled>
+            </snapshots>
+        </pluginRepository>
         <pluginRepository>
             <id>vaadin-prereleases</id>
             <url>http://maven.vaadin.com/vaadin-prereleases</url>