RFR: Deprecate GitLab award emojis for flagging a PR as reviewed

[Robin Westberg]

Before disabling support for GitLab award emojis as review markers, we can start with posting a notification about the preferred way.

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Commit messages:
 - Deprecate award emojis as reviews

Changes: https://git.openjdk.java.net/skara/pull/939/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=939&range=00
  Stats: 38 lines in 3 files changed: 33 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/skara/pull/939.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/939/head:pull/939

PR: https://git.openjdk.java.net/skara/pull/939