Change default Java version to 17 (#290)

Per [Paketo Java RFC 14](https://github.com/paketo-buildpacks/rfcs/blob/main/text/java/0014-selecting-default-java-version.md) we are changing the default version of Java selected by the buildpack to Java 17.

Signed-off-by: Daniel Mikusa <dan@mikusa.com>
Co-authored-by: David O'Sullivan <31728678+pivotal-david-osullivan@users.noreply.github.com>

buildpack.toml

@@ -123,7 +123,7 @@ api = "0.7"
 
   [[metadata.configurations]]
     build = true
-    default = "11"
+    default = "17"
     description = "the Java version"
     name = "BP_JVM_VERSION"