Bump networkx from 2.6.2 to 2.6.3

Bumps [networkx](https://github.com/networkx/networkx) from 2.6.2 to 2.6.3.
- [Release notes](https://github.com/networkx/networkx/releases)
- [Commits](networkx/networkx@networkx-2.6.2...networkx-2.6.3)

---
updated-dependencies:
- dependency-name: networkx
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>