[Bug] Specify utf-8 encoding in version.py

[nashsibanda]

With the recent update to setuptools==70.0.0, the module can no longer be installed in certain python environments. This is due to the version.py script not providing any output (get_git_version() returns None). setuptools versions prior to setuptools==66.0.0 fell back to packaging.version.LegacyVersion, which would provide a PEP440 compliant version number if one wasn't provided. This was removed in setuptools==66.

This PR adds encoding='utf-8' to the Popen command in version.py, which puts stderr and stdout into text mode, returning a string rather than returning a bytestream when read. This prevents a TypeError being raised when .strip() is called on this output (the Exception - indeed, as with all exceptions - is silently caught by the try-except block).

Tested locally.