Increase minimum required Remoting version from 4.2.1 to 4.7 (#7340)

pom.xml

@@ -89,7 +89,7 @@ THE SOFTWARE.
     <!-- Bundled Remoting version -->
     <remoting.version>3071.v7e9b_0dc08466</remoting.version>
     <!-- Minimum Remoting version, which is tested for API compatibility -->
-    <remoting.minimum.supported.version>4.2.1</remoting.minimum.supported.version>
+    <remoting.minimum.supported.version>4.7</remoting.minimum.supported.version>
 
     <spotbugs.effort>Max</spotbugs.effort>
     <spotbugs.threshold>Medium</spotbugs.threshold>

test/pom.xml

@@ -256,7 +256,7 @@ THE SOFTWARE.
                 <artifactItem>
                   <groupId>org.jenkins-ci.main</groupId>
                   <artifactId>remoting</artifactId>
-                  <version>4.2</version>
+                  <version>4.6</version>
                   <type>jar</type>
                   <outputDirectory>${project.build.outputDirectory}/old-remoting</outputDirectory>
                   <destFileName>remoting-unsupported.jar</destFileName>