fix version sort order

[lightmare]

nodenv install --list doesn't sort graal+ce_javaX versions consistently, different java and engine versions are mixed.

Here's a diff of the output before and after this patch:

--- list.master	2021-08-17 21:19:37.451052350 +0200
+++ list.branch	2021-08-17 21:19:51.586984571 +0200
@@ -654,14 +654,14 @@
 graal+ce-19.2.0.1
 graal+ce-19.2.0-dev-b01
 graal+ce-19.2.1
-graal+ce_java11-19.3.0
-graal+ce_java11-19.3.0.2
 graal+ce_java8-19.3.0
 graal+ce_java8-19.3.0.2
-graal+ce_java11-19.3.1
 graal+ce_java8-19.3.1
-graal+ce_java11-20.0.0
 graal+ce_java8-20.0.0
+graal+ce_java11-19.3.0
+graal+ce_java11-19.3.0.2
+graal+ce_java11-19.3.1
+graal+ce_java11-20.0.0
 iojs-0.12.0-dev
 iojs-1.0.0
 iojs-1.x-dev