Bugfix draw_from_gwb_log_uniform_distribution

[Wang-weiYu]

To fix the potential bug described in issue #220

1. add a parameter dictionary in the JumpProposal class.

2. use the parameter name as a key to retrieve the parameter, instead of relying on an index within function draw_from_gwb_log_uniform_distribution() in enterprise_extensions.sampler.JumpProposal.

This modifications seem to avoid potential issues associated with index usage.

[vhaasteren]

This PR looks fine to me. It doesn't pass the linting check though, because of some whitespace:

./enterprise_extensions/sampler.py:542:1: W293 blank line contains whitespace
make: *** [Makefile:39: lint] Error 1
Error: Process completed with exit code 2.

If you delete the whitespace on that line all the checks will likely pass.

[codecov-commenter]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (541dd1f) 37.23% compared to head (2b93550) 37.29%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #221      +/-   ##
==========================================
+ Coverage   37.23%   37.29%   +0.05%     
==========================================
  Files          20       20              
  Lines        3969     3974       +5     
==========================================
+ Hits         1478     1482       +4     
- Misses       2491     2492       +1     

Files	Coverage Δ
enterprise_extensions/sampler.py	38.29% <57.14%> (+0.28%)	⬆️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 541dd1f...2b93550. Read the comment docs.

[Wang-weiYu]

@vhaasteren Thanks for pointing out this to me and testing my modifications! Now, it is fine.

[vhaasteren]

Looks fine to me now, thanks for fixing this