Merge pull request docker-archive#2257 from allencloud/fix-unit-test-…

…command-in-CONTRIBUTION

fix unit test command in CONTRIBUTION.md

Merge pull request docker-archive#2282 from nishanttotla/bump-v1.2.3-rc1

Bump version to v1.2.3-rc1

Merge pull request docker-archive#2215 from joelhandwell/patch-1

Krane project has been closed in favor of Machine

Merge pull request docker-archive#2211 from nishanttotla/bump-1.2.2-rc1

Bump version to 1.2.2-rc1

Merge pull request docker-archive#2207 from dongluochen/bump-1.2.1

Bump version to v1.2.1

Merge pull request docker-archive#2158 from dongluochen/bump-1.2.1rc1

bump 1.2.1-rc1

Merge pull request docker-archive#2118 from vieux/update_changelog

update CHANGELOG.md

Merge pull request docker-archive#2103 from dongluochen/bump-v1.2.0-rc3

Bump version to v1.2.0-rc3

Merge pull request docker-archive#2071 from dongluochen/bump-1.2.0-rc2

Bump version to 1.2.0-rc2

Merge pull request docker-archive#2009 from dongluochen/bump-1.2.0-rc1

Bump version to 1.2.0-rc1