regex to check version fixed

Author: jvazquez-r7

modules/exploits/multi/http/extplorer_upload_exec.rb

@@ -72,7 +72,7 @@ def check
 				return Exploit::CheckCode::Safe
 			end
 
-			if res.body =~ /<version>2\.1\.0RC[012]<\/version>/
+			if res.body =~ /<version>2\.1\.(0RC\d|0|1|2)<\/version>/
 				return Exploit::CheckCode::Vulnerable
 			end