Add Ethan as Lightning App CodeOwners (#15626)

update

(cherry picked from commit 61d3253)

Author: tchaton

.github/CODEOWNERS

@@ -43,10 +43,10 @@
 /tests/tests_lite                           @awaelchli @carmocca @justusschock
 
 # Lightning App
-/src/lightning_app                          @tchaton @lantiga @awaelchli @hhsecond
-/tests/tests_app                            @tchaton @awaelchli @hhsecond
-/tests/tests_app_examples                   @tchaton @awaelchli @hhsecond
-/examples/app_*                             @tchaton @awaelchli @hhsecond
+/src/lightning_app                          @tchaton @lantiga @awaelchli @hhsecond @ethanwharris
+/tests/tests_app                            @tchaton @lantiga @awaelchli @hhsecond @ethanwharris
+/tests/tests_app_examples                   @tchaton @lantiga @awaelchli @hhsecond @ethanwharris
+/examples/app_*                             @tchaton @lantiga @awaelchli @hhsecond @ethanwharris
 
 /.github/CODEOWNERS                  @williamfalcon
 /SECURITY.md                         @williamfalcon