Removed a manual file handler pitfall
It is a simple PR. 

It only removes a manual file handler pitfall from versioneer.py

As stated by [Pylint documentation](https://pylint.pycqa.org/en/latest/technical_reference/features.html)

"
consider-using-with (R1732)
Consider using 'with' for resource-allocating operations Emitted if a resource-allocating assignment or call may be replaced by a 'with' block. By using 'with' the release of the allocated resources is ensured even in the case of an exception.
"