Assign image tag based on the pulsar wheel version

[VJalili]

It can help find a docker image if its tag is set appropriately, e.g., using the version of pulsar wheel used for creating the image.

On my mac I am not able to leverage BASH_REMATCH[1] to extract version number from the wheel filename, since it seems macOS has a different function that overrides the value of this variable: https://stackoverflow.com/a/40457982

Creating draft PR, in case anyone interested and know a workaround.

Alternatively, we might be able to use a method similar to the following:

pulsar/setup.py

Lines 46 to 50 in ddf2fde

	_version_re = re.compile(r'__version__\s+=\s+(.*)')
	with open('pulsar/__init__.py', 'rb') as f:
	version = str(ast.literal_eval(_version_re.search(
	f.read().decode('utf-8')).group(1)))