Add support for NumPy 2.1

Fixes #567

pyproject.toml

@@ -50,7 +50,7 @@ classifiers = [
 ]
 requires-python = ">=3.7"
 dependencies = [
-    "numpy >= 1.21.0, < 2.1",     # v1.21.0 is needed for dtype support of ufuncs, see https://numpy.org/devdocs/release/1.21.0-notes.html#ufunc-signature-and-dtype-generalization-and-casting
+    "numpy >= 1.21.0, < 2.2",     # v1.21.0 is needed for dtype support of ufuncs, see https://numpy.org/devdocs/release/1.21.0-notes.html#ufunc-signature-and-dtype-generalization-and-casting
     "numba >= 0.55, < 0.61",      # v0.55 is needed for support of NumPy 1.21
     "typing_extensions >= 4.0.0", # v4.0.0 is needed for use of Self (Python 3.11+) and Literal (Python 3.8+)
 ]