Add hackz@ to OWNERS files

For voice, speech and content capture.

Test: n/a
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:3bde03b852634ef1006c634251840d991f616ad2)
Merged-In: Ie90de17b4dad7b9e566f62cd03eeed28e3da3f04
Change-Id: Ie90de17b4dad7b9e566f62cd03eeed28e3da3f04

core/java/android/app/assist/OWNERS

@@ -3,3 +3,5 @@ joannechung@google.com
 markpun@google.com
 lpeter@google.com
 tymtsai@google.com
+hackz@google.com
+volnov@google.com
\ No newline at end of file

core/java/android/speech/OWNERS

@@ -2,3 +2,4 @@ volnov@google.com
 eugeniom@google.com
 schfan@google.com
 andreaambu@google.com
+hackz@google.com
\ No newline at end of file

core/java/android/view/contentcapture/OWNERS

@@ -5,3 +5,5 @@ joannechung@google.com
 markpun@google.com
 lpeter@google.com
 tymtsai@google.com
+hackz@google.com
+volnov@google.com
\ No newline at end of file