Use optimised SA of neal

[kotarotanahashi]

Use optimized SA in pyqubo.utils provided by neal

Resolve issue #19

[codecov-io]

Codecov Report

Merging #24 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #24   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          15     15           
  Lines         694    694           
=====================================
  Hits          694    694

Impacted Files	Coverage Δ
pyqubo/utils/solver.py	100% <100%> (ø)	⬆️

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