Change default for [pytest].pytest_plugins to use pytest-cov 2.11.x

[asherf]

2.11.1 (2021-01-20)

• Fixed support for newer setuptools (v42+).
  Contributed by Michał Górny in #451 <https://github.com/pytest-dev/pytest-cov/pull/451>_.

2.11.0 (2021-01-18)

• Bumped minimum coverage requirement to 5.2.1. This prevents reporting issues.
  Contributed by Mateus Berardo de Souza Terra in #433 <https://github.com/pytest-dev/pytest-cov/pull/433>_.
• Improved sample projects (from the examples <https://github.com/pytest-dev/pytest-cov/tree/master/examples>_
  directory) to support running tox -e pyXY. Now the example configures a suffixed coverage data file,
  and that makes the cleanup environment unnecessary.
  Contributed by Ganden Schaffner in #435 <https://github.com/pytest-dev/pytest-cov/pull/435>_.
• Removed the empty console_scripts entrypoint that confused some Gentoo build script.
  I didn't ask why it was so broken cause I didn't want to ruin my day.
  Contributed by Michał Górny in #434 <https://github.com/pytest-dev/pytest-cov/pull/434>_.
• Fixed the missing coverage context <https://coverage.readthedocs.io/en/stable/contexts.html>_
  when using subprocesses.
  Contributed by Bernát Gábor in #443 <https://github.com/pytest-dev/pytest-cov/pull/443>_.
• Updated the config section in the docs.
  Contributed by Pamela McA'Nulty in #429 <https://github.com/pytest-dev/pytest-cov/pull/429>_.
• Migrated CI to travis-ci.com (from .org).

https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst

[Eric-Arellano]

Thanks! PR title nit: would be good to reframe in terms of how this impacts users, e.g. "Change default for [pytest].pytest_plugins to use pytest-cov 2.11.x"