Address hardcoded version number

[PaulJWright]

The most recent release on pypi was 0.93.3 4 months ago, however the version number is hardcoded in this repo here. This means that if a user installs through pip, or manually from git, currently they will believe they are on the same version.

I would recommend looking at how this is addressed by sunpy.

Example

through pip:

(eispac-testing) ➜  eispac git:(main) pip install eispac
(eispac-testing) ➜  eispac git:(main) ipython
Python 3.8.8 (default, Apr 13 2021, 12:59:45)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.22.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import eispac

In [2]: eispac.__version__
Out[2]: '0.93.3'

... or installing by cloning the repo:

(eispac-testing-2) ➜  eispac git:(main) pip install -e .
(eispac-testing-2) ➜  eispac git:(main) ipython
Python 3.8.8 (default, Apr 13 2021, 12:59:45)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.22.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import eispac

In [2]: eispac.__version__
Out[2]: '0.93.3'

RE: openjournals/joss-reviews#4914

[MJWeberg]

Finally added automatically updating version numbers.