package/python-pytest-asyncio: bump to version 0.19.0

Second newline at the end of licence file was removed upstream, so
update license file hash.

[1] https://github.com/pytest-dev/pytest-asyncio/commit/4c7da65d6fcf9d725eccba28ad1ed2083524ee16



Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>