bump cirq to v0.12.0.dev

[balopat]

I forgot to do this at the release of v0.11.

[maffoo]

LGTM

Note that changes merged since the 0.11.0 release have been getting pushed to pypi as pre-release versions and show up in the version history as earlier than the 0.11.0 release: https://pypi.org/project/cirq/#history. We might want to detect this kind of scenario when we attempt to publish to pypi by looking at tags in the git history (if there's a vA.B.C tag in the history, then fail if you try to publish a pre-release vA.B.C.dev). Instead (or in addition), we could add more automation around the release process by having a script that generates the version bump commit so we don't forget to do it.

[balopat]

LGTM

Note that changes merged since the 0.11.0 release have been getting pushed to pypi as pre-release versions and show up in the version history as earlier than the 0.11.0 release: https://pypi.org/project/cirq/#history. We might want to detect this kind of scenario when we attempt to publish to pypi by looking at tags in the git history (if there's a vA.B.C tag in the history, then fail if you try to publish a pre-release vA.B.C.dev). Instead (or in addition), we could add more automation around the release process by having a script that generates the version bump commit so we don't forget to do it.

Agreed that we should put in automation around the release process and potentially more checks and balances. It is especially going to be important in this monorepo world.