Update pyproject.toml: bump mypy to 1.15.0

v1.14.1 is the current version, and python/mypy#17485 has the "upnext" label, so 1.15 should do

Author: wyattscarpenter

pyproject.toml

@@ -30,7 +30,7 @@ pyarrow = ["pyarrow"]
 
 [tool.poetry.dev-dependencies]
 pytest = "^7.1.2"
-mypy = "^1.10.1"
+mypy = "^1.15.0"
 pylint = ">=2.12.0"
 black = "^22.3.0"
 pytest-dotenv = "^0.5.2"
@@ -56,4 +56,4 @@ minversion = "6.0"
 log_cli = "false"
 log_cli_level = "INFO"
 testpaths = ["tests"]
-env_files = ["test.env"]
+env_files = ["test.env"]