Update tests for PL 0.31 to remove deprecated functions

[mlxd]

Context: PennyLane v0.30.0-dev has removed support for previously deprecated functions, as defined in https://docs.pennylane.ai/en/stable/development/deprecations.html. This PR updates those functions to the new supported syntax.

Description of the Change: As above. In addition, due to an ongoing issue with RTD builds using unaligned versions of setuptools and pip, we create a subtle change to the RTD builder to fix the package versions until readthedocs/readthedocs.org#10287 becomes usable. In addition, to avoid CI issues, CYBot is now GHBot and will auto-update the package versions in the CI.

Benefits: Fixes currently failing tests.

Possible Drawbacks:

Related GitHub Issues:

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit .github/CHANGELOG.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[codecov]

Codecov Report

Merging #448 (d61e94b) into master (7bbe3b4) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #448   +/-   ##
=======================================
  Coverage   99.82%   99.82%           
=======================================
  Files          50       50           
  Lines        4654     4654           
=======================================
  Hits         4646     4646           
  Misses          8        8           

Impacted Files	Coverage Δ
pennylane_lightning/_version.py	100.00% <100.00%> (ø)

[vincentmr]

Looks good to me. Thanks @mlxd

[AmintorDusko]

Nice work, short and sweet! I'm just waiting for the CIs to conclude successfully and will approve!