RFR: 827: Copyright year differences can be regarded as a clean backport [v2]

[Zhao Song]

> As many user requested, when determining whether a backport is clean, our bot should ignore copyright year difference.

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

  update

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Changes:
  - all: https://git.openjdk.org/skara/pull/1556/files
  - new: https://git.openjdk.org/skara/pull/1556/files/366b25e8..0af301eb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1556&range=01
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1556&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/skara/pull/1556.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1556/head:pull/1556

PR: https://git.openjdk.org/skara/pull/1556