gitaly needs gitlab-labkit ~> 0.15.0

--- a/Gemfile
+++ b/Gemfile
@@ -297,7 +297,7 @@
 gem 'premailer-rails', '~> 1.10', '>= 1.10.3'
 
 # LabKit: Tracing and Correlation
-gem 'gitlab-labkit', '~> 0.14.0'
+gem 'gitlab-labkit', '~> 0.15.0'
 # Thrift is a dependency of gitlab-labkit, we want a version higher than 0.14.0
 # because of https://gitlab.com/gitlab-org/gitlab/-/issues/321900
 gem 'thrift', '>= 0.14.0'