Update dependency mypy to ~=1.20.2

Author: renovate[bot]

pyproject.toml

@@ -15,7 +15,7 @@ requires-python = "~=3.14.0"
 [dependency-groups]
 dev = [
     "coverage~=7.12.0",
-    "mypy~=1.19.0",
+    "mypy~=1.20.2",
     "pytest~=9.0.0",
     "pytest-cov~=7.0.0",
     "pytest-randomly~=4.0.1",