Merge pull request #34393 from chuckbutler/juju-reviewers-definition

Automatic merge from submit-queue

Adds OWNERS file for cluster/juju

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**What this PR does / why we need it**: Adds an OWNERS file for the `cluster/juju` directory. This was requested by @mikedanese  over on https://github.com/kubernetes/kubernetes/pull/31736#issuecomment-252391221

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, #<issue_number>, ...)` format, will close that issue when PR gets merged)*: N/A

**Special notes for your reviewer**: N/A

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Inserts @chuckbutler and @mbruzek as reviewers for the juju cluster directory.
Additional assignee of @marcoceppi and @castrojo to help handle overflow.

cluster/juju/OWNERS

@@ -0,0 +1,8 @@
+assignees:
+  - chuckbutler
+  - mbruzek
+  - marcoceppi
+  - castrojo
+owners:
+  - chuckbutler
+  - mbruzek