Prepare 4.0.0 release (#248)

Author: Malax

Diff for: README.md

@@ -6,8 +6,8 @@ Command line tool to deploy JVM applications directly to Heroku without pushing
 It will automatically include and configure a Tomcat server via [webapp-runner](https://github.com/heroku/webapp-runner) if a WAR file is deployed.
 
 > [!IMPORTANT]
-> This repository previously contained Heroku's Maven Plugin for deploying JVM applications. This plugin will be sunset
-> soon. Customers currently using the Maven Plugin can then use the new Heroku JVM application deployer CLI to deploy
+> This repository previously contained Heroku's Maven Plugin for deploying JVM applications. This plugin is no longer
+> maintained. Customers currently using the Maven Plugin can use the new Heroku JVM application deployer CLI to deploy
 > JAR and WAR files to Heroku without using Git.
 >
 > The code of the last Heroku Maven plugin release can be found here:

Diff for: pom.xml

@@ -4,7 +4,7 @@
 
   <groupId>com.heroku</groupId>
   <artifactId>heroku-jvm-application-deployer</artifactId>
-  <version>4.0.0-RC3-SNAPSHOT</version>
+  <version>4.0.0-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <name>Heroku JVM Application Deployer</name>