RFR: 2310: Add missing commas in copyright years

[Pavel Rappo]

Please review this utmost trivial change.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/skara/pull/1664/files
  Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1664&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2310
  Stats: 39 lines in 39 files changed: 0 ins; 0 del; 39 mod
  Patch: https://git.openjdk.org/skara/pull/1664.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1664/head:pull/1664

PR: https://git.openjdk.org/skara/pull/1664