Add Ashish Singh to codeowners (#14592)

Signed-off-by: Ashish Singh <ssashish@amazon.com>

Author: ashking94

.github/CODEOWNERS

@@ -11,7 +11,7 @@
 #   3. Use the command palette to run the CODEOWNERS: Show owners of current file command, which will display all code owners for the current file.
 
 # Default ownership for all repo files
-* @anasalkouz @andrross @Bukhtawar @CEHENKLE @dblock @dbwiddis @gbbafna @kotwanikunal @mch2 @msfroh @nknize @owaiskazi19 @reta @Rishikesh1159 @sachinpkale @saratvemulapalli @shwetathareja @sohami @VachaShah
+* @anasalkouz @andrross @ashking94 @Bukhtawar @CEHENKLE @dblock @dbwiddis @gbbafna @kotwanikunal @mch2 @msfroh @nknize @owaiskazi19 @reta @Rishikesh1159 @sachinpkale @saratvemulapalli @shwetathareja @sohami @VachaShah
 
 /modules/transport-netty4/ @peternied