chore: vouch Rohan170603 (#4501)

Adds `Rohan170603` to the list of vouched outside contributors so their
PRs aren't auto-closed by the vouch check.

Closes #4498

Author: matt-aitken

.github/VOUCHED.td

@@ -25,4 +25,5 @@ ThullyoCunha
 ConProgramming
 saasjesus
 brentshulman-silkline
-Leafgard
+Leafgard
+Rohan170603