add pytest dev dependency

.python-version

@@ -0,0 +1 @@
+3.13

pyproject.toml

@@ -6,7 +6,7 @@ authors = [
 ]
 description = 'High-performance processing and analysis of non-hierarchical VLSI designs'
 readme = "README.rst"
-requires_python = ">=3.8"
+requires-python = ">=3.10,<3.14"
 dependencies = [
     "numpy>=1.17.0",
     "lark>=1.3.0",
@@ -30,3 +30,8 @@ homepage = "https://github.com/s-holst/kyupy"
 requires = ["hatchling"]
 build-backend = "hatchling.build"
 
+[dependency-groups]
+dev = [
+    "pytest>=9.0.1",
+]
+