MNG-5297: Mark <prerequisites> as deprecated for compile-time enforcement.

MNG-4840 indicates that the Enforcer plugin should be
preferred to <prerequisites> for compile-time Maven version enforcement.
Indicate that in the documentation, making clear that it's still
supported for runtime requirements for a plugin.

Signed-off-by: Jason van Zyl <jason@tesla.io>

closes #51

maven-model/src/main/mdo/maven.mdo

@@ -3483,9 +3483,13 @@
           <type>String</type>
           <defaultValue>2.0</defaultValue>
           <description><![CDATA[
-            The minimum version of Maven required to build the project.<br />
-            If this project builds a plugin, this is in addition the minimum version of Maven required to use
-            the resulting plugin.]]>
+            For a plugin project, the minimum version of Maven required to use
+            the resulting plugin.<br>
+            For specifying the minimum version of Maven required to build a
+            project, this element is <b>deprecated</b>. Use the Maven Enforcer
+            Plugin's <a href="https://maven.apache.org/enforcer/enforcer-rules/requireMavenVersion.html"><code>requireMavenVersion</code></a>
+            rule instead.
+            ]]>
           </description>
           <required>false</required>
         </field>

pom.xml

@@ -137,6 +137,9 @@
     <contributor>
       <name>Anton Tanasenko</name>
     </contributor>
+    <contributor>
+      <name>Joseph Walton (MNG-5297)</name>
+    </contributor>
   </contributors>
 
   <prerequisites>