NetworkX 2.6.1 released

[Jarrod Millman]

I am happy to announce NetworkX 2.6.1 (2.6.0 had a minor issue)! This
release has a larger than normal number of changes in preparation for
the upcoming 3.0 release. The current plan is to release 2.7 near the
end of summer and 3.0 in late 2021.

The focus of the 3.0 release is on addressing years of technical debt
and making it easier to contribute. The 2.6 release deprecates over
30 functions. It also makes major changes to our default
dependencies. We no longer depend on the "decorator" library. More
importantly, NumPy, SciPy, Matplotlib, and Pandas are now default
requirements. While we've made these core libraries of the scientific
Python ecosystem default dependencies, much of NetworkX still works
without these libraries and we expect that to continue. Be assured
that we test NetworkX with and without the dependencies, so if you do
**not** use functions that depend on external libraries you can
install NetworkX using pip with the `--no-deps` flag.

This release supports Python 3.7-3.9 and contains many new features.
It is the result of almost a year of work with over 363 pull requests
by 91 contributors. If you have code that imports NetworkX, please
take some time to check that you are able to update your code to work
with the new release.

The 2.6 release announcement is here:
https://networkx.org/documentation/stable/release/release_2.6.html

For more information, please visit our website
- http://networkx.org
and our gallery of examples
- https://networkx.org/documentation/latest/auto_examples/index.html

Best regards,
Jarrod