build: drop oldest-supported-numpy from build requirements

The package is pure Python, so numpy is not needed to build it, and
numpy has deprecated oldest-supported-numpy. Build tools that do not
install arbitrary build requirements (for example rules_py's uv sdist
builder) fail on it.

Author: taughz

pyproject.toml

@@ -78,7 +78,7 @@ ros-humble = [
 
 [build-system]
 
-requires = ["setuptools", "oldest-supported-numpy"]
+requires = ["setuptools"]
 build-backend = "setuptools.build_meta"
 
 [tool.setuptools]