Update numpy requirement from <1.27 to <2.1

Updates the requirements on [numpy](https://github.com/numpy/numpy) to permit the latest version.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/RELEASE_WALKTHROUGH.rst)
- [Commits](numpy/numpy@v0.2.0...v2.0.0)

---
updated-dependencies:
- dependency-name: numpy
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -33,7 +33,7 @@ tests = [
     "coverage==7.5.0",
     "pytest>=3.5.0",
     "pytest-cov==5.0.0",
-    "numpy<1.27",
+    "numpy<2.1",
 ]
 docs = [
     "pydata-sphinx-theme==0.15.3",