Replace raising QiskitError by AlgorithmError

[woodsp-ibm]

Summary

In a couple of places QiskitError was directly raised. Normally the algorithms raise an AlgorithmError so given algorithms has been moved out of Qiskit, to better distinguish the exception to algorithms, and to make it consistent with elsewhere I changed the couple of places to raise AlgorithmError instead.

Resolves #30

Details and comments

As AlgorithmError extends QiskitError its unlikely that this has any impact on anyone. I added a release note in case. Indeed the test_pvqd unit test, that checked an error condition continued to work unchanged - though I did change it to AlgorithmError as that is really what should be expected now.

Of course I ran tests, and built html locally and it was all good.... such a small change.... I did not run lint!

tools/check_copyright.py:1:0: R0401: Cyclic import (qiskit_algorithms -> qiskit_algorithms.minimum_eigensolvers -> qiskit_algorithms.minimum_eigensolvers.adapt_vqe) (cyclic-import)

[coveralls]

Pull Request Test Coverage Report for Build 5824240848

• 4 of 7 (57.14%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.994%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_algorithms/minimum_eigensolvers/adapt_vqe.py	1	2	50.0%
qiskit_algorithms/optimizers/snobfit.py	1	2	50.0%
qiskit_algorithms/time_evolvers/pvqd/pvqd.py	2	3	66.67%

Totals
Change from base Build 5692627482:	0.0%
Covered Lines:	6395
Relevant Lines:	7106

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💛 - Coveralls

[Cryoris]

LGTM!