Update dependency tomlkit to v0.15.0

Author: renovate[bot]

requirements.txt

@@ -20,7 +20,7 @@ pyright==1.1.409
 pytest==9.0.3
 pytest-cov==7.1.0
 tomli==2.4.1
-tomlkit==0.14.0
+tomlkit==0.15.0
 typing_extensions==4.15.0
 wrapt==2.1.2
 zipp>=3.23.1 # not directly required, pinned by Snyk to avoid a vulnerability