- Update to 5.1.2:
* #2270: Fixed self reference in function-scoped fixtures defined plugin classes: previously self would be a reference to a test class, not the plugin class.
* #570: Fixed long standing issue where fixture scope was not respected when indirect fixtures were used during parametrization.
* #5782: Fix decoding error when printing an error response from --pastebin.
* #5786: Chained exceptions in test and collection reports are now correctly serialized, allowing plugins like pytest-xdist to display them properly.

- Update to 5.1.1
* Removed:
+ Request.getfuncargvalue: use Request.getfixturevalue instead.
+ pytest.raises and pytest.warns no longer support strings as the second argument.
+ message parameter of pytest.raises.
+ pytest.raises, pytest.warns and ParameterSet.param now use native keyword-only
syntax. This might change the exception message from previous versions, but
they still raise TypeError on unknown keyword arguments as before.
+ pytest.config global variable.
+ tmpdir_factory.ensuretemp method.
+ pytest_logwarning hook.
+ RemovedInPytest4Warning warning type.
+ request is now a reserved name for fixtures.
+ Removed unused support code for unittest2.
+ pytest.fail, pytest.xfail and pytest.skip no longer support bytes
for the message argument.
* New Config.invocation_args attribute containing the unchanged arguments passed to pytest.main().
* New NUMBER option for doctests to ignore irrelevant differences in floating-point numbers
* JUnit XML now includes a timestamp and hostname in the testsuite tag.
* Fix RuntimeError/StopIteration when trying to collect package with “__init__.py” only.
* Warnings issued during pytest_configure are explicitly not treated as errors,
even if configured as such, because it otherwise completely breaks pytest.
* The XML file produced by --junitxml now correctly contain a root element.
* Fixed using multiple short options together in the command-line (for example -vs) in Python 3.8+.