main into dev pre 2.0.1

I added to line 35. I assumed the asterisk on 3.3 meant all versions of 3.3 ex (3.3.1, 3.3.2) are all excluded from the matplotlib. 

Is this correct?

Removed outdated Zenodo DOI from README.md

…aspologic-org#1002)

* Fix seaborn syntax

* fixed padding of a similarity amtrix for graph matching

* fixing mypy complaint from _adj_pad

* use naive padding for similarity

* add a test

* Revert "Fix seaborn syntax"

This reverts commit fd38e05.

* try to fix ipython error in doc generation

* just make sure the original S had the right shape

* run black

* fix tests

Co-authored-by: Benjamin Pedigo <benjamindpedigo@gmail.com>

* Editing contributing guidelines 

My edits were based on my experience with getting set up on GitHub. I added some minor changes of things I wish I had read while I was trying to set up my account.

* fix typo

Co-authored-by: Benjamin Pedigo <benjamindpedigo@gmail.com>

check_dirloop: You could try replacing the isinstance checks with simple type checks, since bool is a subclass of int and isinstance will also return True if the argument is an int.

check_r: You could try replacing the np.issubdtype check with a simple type check, since float is a subclass of int and np.issubdtype will also return True if the argument is an int.

check_rel_sbm: You could try replacing the nested for loops with a single loop over the flattened array, using the ndarray.flat attribute