chore(deps): update logstash docker tag to v8.15.1

[renovate]

This PR contains the following updates:

Package	Update	Change
logstash	minor	8.12.0 -> 8.15.1

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.60%. Comparing base (2b73548) to head (20767f3).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #156   +/-   ##
=======================================
  Coverage   95.60%   95.60%           
=======================================
  Files          11       11           
  Lines          91       91           
=======================================
  Hits           87       87           
  Misses          4        4           

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