RFR: 880: Map jdk.jpackage to core-libs-dev

[Kevin Rushforth]

The `jpackage` tool moved from the `jdk.incubator.jpackage` module to `jdk.jpackage` in JDK 16. The `jdk.json` config file needs to be updated accordingly so that `jpackage` reviews are sent to `core-libs-dev`.

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Commit messages:
 - 880: Map jdk.jpackage to core-libs-dev

Changes: https://git.openjdk.java.net/skara/pull/996/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=996&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-880
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/996.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/996/head:pull/996

PR: https://git.openjdk.java.net/skara/pull/996