Update bundled gems list at 150bd6e242 [ci skip]

NEWS.md

@@ -167,7 +167,7 @@ Note: We're only listing outstanding class updates.
 *   The following bundled gems are updated.
     * minitest 5.16.0
     * net-imap 0.2.3
-    * rbs 2.5.0
+    * rbs 2.5.1
     * typeprof 0.21.2
     * debug 1.5.0
 *   The following default gems are now bundled gems.