Update dependency blacken-docs to v1.15.0 (#463)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

poetry.lock

@@ -35,7 +35,7 @@ yarl = ">=1.6.0"
 [tool.poetry.dev-dependencies]
 aresponses = "2.1.6"
 black = "23.3.0"
-blacken-docs = "1.13.0"
+blacken-docs = "1.15.0"
 codespell = "2.2.5"
 covdefaults = "2.3.0"
 coverage = {version = "7.2.7", extras = ["toml"]}