RFR: CODETOOLS-7903168: Update openjdk/jtreg repo to require 1 Reviewer

[Jonathan Gibbons]

Please review a small change to require a "R"eviewer for changes to the jtreg repo

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Commit messages:
 - CODETOOLS-7903168: Update openjdk/jtreg repo to require 1 Reviewer

Changes: https://git.openjdk.java.net/jtreg/pull/80/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jtreg&pr=80&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903168
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/80.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/80/head:pull/80

PR: https://git.openjdk.java.net/jtreg/pull/80