Use modern type hint syntax throughout the codebase

This commit replaces the use of 'Union' type hints with the modern '|' syntax in multiple files for better readability and conciseness. Additionally, it removes unnecessary imports of 'Union' from the 'typing' module.

Signed-off-by: Marcelo Trevisani <[email protected]>

grayskull/strategy/py_base.py

@@ -358,7 +358,7 @@ def _fix_list_requirements(key_deps: str) -> list:
             if isinstance(val_deps, str):
                 val_deps = [val_deps]
             for val in val_deps:
-                if isinstance(val, (tuple, list)):
+                if isinstance(val, tuple | list):
                     list_req.extend(list(map(str, val)))
                 else:
                     list_req.append(str(val))