Change from sakal@webrtc.org to xalep@webrtc.org in OWNERS files.

Auto generated with:

git grep -l "sakal@webrtc.org" | xargs sed -i '' -e 's/sakal/xalep/g'

No-Try: True
Bug: webrtc:12673
Change-Id: Ic1d4e8c655725d490a0e2b0d492e42edc9aa919c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215147
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33722}

rtc_base/java/src/org/webrtc/OWNERS

@@ -1,2 +1,2 @@
 magjed@webrtc.org
-sakal@webrtc.org
+xalep@webrtc.org