metrics/histograms: Add mlippautz

Add mlippautz to
- blink/ for BlinkGC.*
- v8/ for general reviews

Change-Id: I6957c8cdbb7e7dc9ecbd60e39192ba095aff3730
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2642324Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846013}

tools/metrics/histograms/histograms_xml/blink/OWNERS

 schenney@chromium.org
+# For BlinkGC.* and related changes.
+mlippautz@chromium.org
\ No newline at end of file

tools/metrics/histograms/histograms_xml/v8/OWNERS

+mlippautz@chromium.org
\ No newline at end of file