bump python version for ruff and mypy

Author: iurisilvio

pyproject.toml

@@ -7,7 +7,7 @@ target = ["test", "roboflow"]
 tests = ["B201", "B301"]
 
 [tool.ruff]
-target-version = "py38"
+target-version = "py39"
 line-length = 120
 
 [tool.ruff.lint]
@@ -100,7 +100,7 @@ banned-module-level-imports = [
 ]
 
 [tool.mypy]
-python_version = "3.8"
+python_version = "3.9"
 exclude = ["^build/"]
 
 [[tool.mypy.overrides]]