Bump execnet from 1.7.1 to 1.8.0 in /requirements

[dependabot]

Bumps execnet from 1.7.1 to 1.8.0.

Changelog

Sourced from execnet's changelog.

1.8.0 (2021-01-27)

• Dropped support for Python 3.4.

• [#118](https://github.com/pytest-dev/execnet/issues/118) <https://github.com/pytest-dev/execnet/pull/118>: Fixed internal leak that should make execnet execute remote code in the main thread more often; previously it would sometimes spawn a thread to execute a remote_exec call, even when the caller didn't issue multiple remote_exec calls at the same time. Some frameworks require code to execute in the main thread, so the previous behavior would break them on occasion (see pytest-dev/pytest-xdist#620 <https://github.com/pytest-dev/pytest-xdist/issues/620> for an example).

• [#115](https://github.com/pytest-dev/execnet/issues/115) <https://github.com/pytest-dev/execnet/pull/115>__: Current working directory is now restored when calling script/socketserver.py. The script now also loops by default when called from the command-line.

Commits

• 802aef1 Release 1.8.0
• b261e95 Merge pull request #115 from yili1992/master
• c8bedac [pre-commit.ci] auto fixes from pre-commit.com hooks
• cdb3f1c Update CHANGELOG for #115
• 4a50d27 fix(socketserver): current workdir be modified when loop =True
• 4272107 Merge pull request #118 from graingert/waitclose-in-rinfo-call
• f0cfea4 Update CHANGELOG
• 84ffea8 waitclose in _rinfo() call
• 0785570 Merge pull request #117 from nicoddemus/github-actions
• e24a036 Use explicit matrix to configure GH jobs
• Additional commits viewable in compare view

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