Upgrade minimum required version of Pennylane to v0.40

[josephleekl]

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---

Context:
Pennylane Lightning v0.40 is not compatible with Pennylane version <0.40. This PR upgrades the pennylane requirement.

Description of the Change:

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[sc-82212]

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 27.36%. Comparing base (b87e87e) to head (4280d52).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
pennylane_lightning/core/lightning_base.py	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (b87e87e) and HEAD (4280d52). Click for more details.

HEAD has 3 uploads less than BASE

Flag	BASE (b87e87e)	HEAD (4280d52)
	9	6

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #1033       +/-   ##
===========================================
- Coverage   38.90%   27.36%   -11.55%     
===========================================
  Files          48       29       -19     
  Lines        3177     2646      -531     
===========================================
- Hits         1236      724      -512     
+ Misses       1941     1922       -19     

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[multiphaseCFD]

Thanks @josephleekl. Don't forget to change the version from rc{n} to rc{n+1}.

[multiphaseCFD]

@josephleekl could you please get this PR updated with the latest master branch? Looks like we have to get this PR merged ASAP. CC: @maliasadi

[multiphaseCFD]

LGTM! Thanks @josephleekl for taking care of it.

[maliasadi]

🥳