Add janitors to the OWNERS file am: 3ce6c81cf8 am: 525b3c44c5

Original change: https://android-review.googlesource.com/c/platform/external/opencensus-java/+/3423792

Change-Id: I943d9b8671363bd38da93e8eed65a6e65bf1f040
Signed-off-by: Automerger Merge Worker <[email protected]>