Bump version number in dokku-installer.rb

Just bumping the version number to bring it up-to-date with the rest of the project.

contrib/dokku-installer.rb

@@ -21,7 +21,7 @@ if ARGV[0] == "onboot"
 	exit
 end
 
-version 	= "v0.2.0"
+version 	= "v0.2.1"
 dokku_root	= ENV["DOKKU_ROOT"] || "/home/dokku"
 admin_key 	= `cat /root/.ssh/authorized_keys`.split("\n").first
 hostname 	= `bash -c '[[ $(dig +short $HOSTNAME) ]] && echo $HOSTNAME || curl icanhazip.com'`.strip
@@ -119,4 +119,4 @@ __END__
 		update();
 	</script>
 </body>
-</html>
+</html>