Bump version to 0.560

Bump version to 0.550

Set version to 0.540.

Bump version to 0.530

Bump version to 0.521

Bump version to 0.520 (python#3689)

Bump version to 0.511 (python#3344)

Bump version to 0.510

Bump version to 0.501

There was a problem with uploading packages for 0.500 and PyPI doesn't
like uploading multiple different packages for a single version, so
bumping version. There are no functional changes from 0.500.

Fix test failure caused by version being 0.500 (python#2936)

Fix replace() that used the mypy version as the thing to replace,
which happened to match the string '0.5000' in the output of a test
case.