chore(Crons): Log message for debugging Crons check-ins.

[antonpirker]

A debug message to see what check-ins are send including the monitor_slug and the check-in status.

If you set sentry_sdk.init(.., debug=True) then there will be a debug log message:
"[Crons] Captured check-in ({check-in-id}): {monitor-slug} -> {status}"

[szokeasaurusrex]

might be worth adding a test – although idk whether we typically test such things. If we don't, I suppose this is fine

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.08%. Comparing base (378fe81) to head (c490a80).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4686      +/-   ##
==========================================
+ Coverage   85.02%   85.08%   +0.06%     
==========================================
  Files         156      156              
  Lines       15856    15858       +2     
  Branches     2684     2684              
==========================================
+ Hits        13481    13493      +12     
+ Misses       1595     1584      -11     
- Partials      780      781       +1     

Files with missing lines	Coverage Δ
sentry_sdk/crons/api.py	100.00% <100.00%> (ø)

... and 4 files with indirect coverage changes