Updates include:
- websockex: updated from 0.4.3 to 0.5.1 to enable telemetry support
- credo: updated from 1.7.15 to 1.7.16
- ex_doc: updated from 0.40.0 to 0.40.1

Version references in README.md and the getting started guide have been
synchronized with this release. The mix.lock file has been updated to reflect
the new dependency tree.