Appease pylint 1.6.2:

Source-Link: https://togithub.com/googleapis/synthtool/commit/eaef28efd179e6eeb9f4e9bf697530d074a6f3b9
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:f8ca7655fa8a449cadcabcbce4054f593dcbae7aeeab34aa3fcc8b5cf7a93c9e

* fix: edit units for time in tests

* fix: updates timestamp precision for additional tests

* fix: tweaking another time resolution

* fix: tweaking yet another time resolution

* trying out an option

* minor syntax tweak, added comma

* fix linting

* test addition of dtypes to results

* Update tests/system/test_gbq.py

* Update tests/system/test_read_gbq.py

* add tests to dtypes dict

* Update tests/system/test_read_gbq.py

* Update tests/system/test_gbq.py

* try again

* add version check and skipif on several tests

* Update tests/system/test_read_gbq.py

* blacken/lint the file

* Adds a skipif statement to an additional test

* blacken the code

…[autoapprove] (#655)

Source-Link: googleapis/synthtool@4826337
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:60a63eddf86c87395b4bb394fdddfe30f84a7726ee8fe0b758ea132c2106ac75

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

Source-Link: googleapis/synthtool@e3a1277
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:452901c74a22f9b9a3bd02bce780b8e8805c97270d424684bff809ce5be8c2a2

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

Closes #654.

🤖 I have created a release \*beep\* \*boop\* 
---
## [1.24.0](https://www.github.com/googleapis/google-auth-library-python/compare/v1.23.0...v1.24.0) (2020-12-11)


### Features

* add Python 3.9 support, drop Python 3.5 support ([#655](https://www.github.com/googleapis/google-auth-library-python/issues/655)) ([6de753d](https://www.github.com/googleapis/google-auth-library-python/commit/6de753d585254c813b3e6cbde27bf5466261ba10)), closes [#654](https://www.github.com/googleapis/google-auth-library-python/issues/654)


### Bug Fixes

* avoid losing the original '_include_email' parameter in impersonated credentials ([#626](https://www.github.com/googleapis/google-auth-library-python/issues/626)) ([fd9b5b1](https://www.github.com/googleapis/google-auth-library-python/commit/fd9b5b10c80950784bd37ee56e32c505acb5078d))


### Documentation

* fix typo in import ([#651](https://www.github.com/googleapis/google-auth-library-python/issues/651)) ([3319ea8](https://www.github.com/googleapis/google-auth-library-python/commit/3319ea8ae876c73a94f51237b3bbb3f5df2aef89)), closes [#650](https://www.github.com/googleapis/google-auth-library-python/issues/650)
---


This PR was generated with [Release Please](https://github.com/googleapis/release-please).

The continuous kokoro test should use the [same configuration as the
pre-submit](https://github.com/googleapis/python-datastore/blob/main/.kokoro/presubmit/presubmit.cfg)

* chore(main): release 2.12.1

* Update CHANGELOG.md

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Anna Cocuzzo <63511057+acocuzzo@users.noreply.github.com>

Adds a SpannerPickleType that can be used as the implementation for
the standard SQLAlchemy PickleType. The SpannerPickleType ensures that
the binary values are encoded/decoded to/from base64 strings, which is
how Spanner stores binary values.

Fixes #654

* tests: speed up retry conf tests running in parallel

* update conftest readme

* update noxfile and comments

* check test session args

* lint