Update pyproject.toml

Co-authored-by: Davide Marchegiani <[email protected]>

Author: leoberhelman

pyproject.toml

@@ -8,7 +8,8 @@ authors = [
 ]
 description = "Collection of tools for UM fieldsfiles."
 license = { file = "LICENSE" }
-    keywords = ["UM", "UM utilities", "UM fields files", "umfile_utils"]
+keywords = ["UM", "UM utilities", "UM fields files", "umfile_utils"]
+requires-python = ">=3.10"
 dependencies = [
     "mule",
     "numpy <2",