Update CODEOWNERS
I was wondering why Ignat is never added as code reviewer automatically.
Turns out that the GitHub handle is wrong. Fix it. Now I no longer need
to remember to add important people for code review manually.
# Default reviewer set
* @vixentael @Lagovas
-/src/soter/ @vixentael @Lagovas @ilammy @storojs72 @secumod
-/src/themis/ @vixentael @Lagovas @ilammy @storojs72 @secumod
+/src/soter/ @vixentael @Lagovas @ilammy @storojs72 @ignatk
+/src/themis/ @vixentael @Lagovas @ilammy @storojs72 @ignatk
# Build system
Makefile @vixentael @Lagovas @shadinua
