RFR: 2587: Notify core-libs mailing list for src/jdk.incubator.vector changes

[Erik Joelsson]

Map `src/jdk.incubator.vector` to the core-libs label for the JDK repository.

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Commit messages:
 - SKARA-2587

Changes: https://git.openjdk.org/skara/pull/1739/files
  Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1739&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2587
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/skara/pull/1739.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1739/head:pull/1739

PR: https://git.openjdk.org/skara/pull/1739