chore: release 2.1.0 (googleapis#130)

* chore: release 2.1.0

* Update CHANGELOG.md

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chore: release 2.0.1 (googleapis#117)

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chore: release 2.0.0 (googleapis#114)

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chore: release 2.0.0-dev1 (googleapis#110)

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chore: release 1.15.3 (googleapis#98)

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chore: release 1.15.2 (googleapis#96)

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chore: release 1.15.1 (googleapis#80)

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chore: release 1.15.0 (googleapis#69)

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chore: release 1.14.0 (googleapis#62)

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chore: release 1.13.2 (googleapis#48)

* updated CHANGELOG.md [ci skip]

* updated setup.cfg [ci skip]

* updated setup.py

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