Update README.md (python-graphblas#404)

* Update README.md

Adds Python version badges

optional dependencies copied from docs

* Update pyproject.toml

Add Sultan Orazbayev as maintainer

README.md

@@ -2,6 +2,7 @@
 
 [![conda-forge](https://img.shields.io/conda/vn/conda-forge/python-graphblas.svg)](https://anaconda.org/conda-forge/python-graphblas)
 [![pypi](https://img.shields.io/pypi/v/python-graphblas.svg)](https://pypi.python.org/pypi/python-graphblas/)
+![PyPI - Python Version](https://img.shields.io/pypi/pyversions/python-graphblas)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://github.com/python-graphblas/python-graphblas/blob/main/LICENSE)
 [![Tests](https://github.com/python-graphblas/python-graphblas/workflows/Tests/badge.svg?branch=main)](https://github.com/python-graphblas/python-graphblas/actions)
 [![Docs](https://readthedocs.org/projects/python-graphblas/badge/?version=latest)](https://python-graphblas.readthedocs.io/en/latest/)
@@ -32,6 +33,15 @@ $ pip install python-graphblas
 ```
 This will also install the [SuiteSparse:GraphBLAS](https://github.com/DrTimothyAldenDavis/GraphBLAS) compiled C library.
 
+### Optional Dependencies
+
+The following are not required by python-graphblas, but may be needed for certain functionality to work.
+
+- `pandas` – required for nicer `__repr__`;
+- `matplotlib` – required for basic plotting of graphs;
+- `scipy` – used in io module to read/write `scipy.sparse` format;
+- `networkx` – used in `io` module to interface with `networkx` graphs.
+
 ## Description
 Currently works with [SuiteSparse:GraphBLAS](https://github.com/DrTimothyAldenDavis/GraphBLAS), but the goal is to make it work with all implementations of the GraphBLAS spec.
 

pyproject.toml

@@ -19,6 +19,7 @@ authors = [
 maintainers = [
     {name = "Erik Welch", email = "[email protected]"},
     {name = "Jim Kitchen", email = "[email protected]"},
+    {name = "Sultan Orazbayev", email = "[email protected]"},
 ]
 keywords = [
     "graphblas",