Fix apply enum

[phi-friday]

When I looked at where Events is used, I realized that it would be better to inherit from Enum.

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.01%. Comparing base (aed6a25) to head (89f65dc).
Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
bayes_opt/event.py	90.90%	1 Missing ⚠️
bayes_opt/logger.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #505      +/-   ##
==========================================
- Coverage   96.19%   96.01%   -0.18%     
==========================================
  Files          10       10              
  Lines         867      879      +12     
==========================================
+ Hits          834      844      +10     
- Misses         33       35       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[till-m]

Hey @phi-friday,

You're right that enums should be used, but the current Logger setup has deeper issues beyond that. The ScreenLogger, JSONLogger, etc., aren't working well for several reasons. I’d prefer a full overhaul, moving away from the observer pattern entirely, so from my perspective this PR isn’t worth merging as a quick fix.

[phi-friday]

i agree.