Add deprecation message to Scope.transaction

[antonpirker]

This is the first part of #3482

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.51%. Comparing base (d0d70a5) to head (ceb1a23).
Report is 8 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4221      +/-   ##
==========================================
+ Coverage   79.48%   79.51%   +0.03%     
==========================================
  Files         141      141              
  Lines       15809    15810       +1     
  Branches     2703     2703              
==========================================
+ Hits        12565    12572       +7     
+ Misses       2382     2380       -2     
+ Partials      862      858       -4     

Files with missing lines	Coverage Δ
sentry_sdk/scope.py	86.16% <100.00%> (+0.01%)	⬆️

... and 4 files with indirect coverage changes

[szokeasaurusrex]

The warning looks good, but it seems like we still use Scope.transaction several places throughout the codebase.

I believe we should first remove those usages, then add the deprecation warning afterwards. Unless, is there some reason why we should instead do this change first?

[antonpirker]

Yes you are right. Then it is not worth the effort. Closing this.