Use valid SPDX ID

ecederstrand · web-flow · commit 98f9eb6f3b76 · 2026-04-27T14:36:54.000+02:00
diff --git a/pyproject.toml b/pyproject.toml
@@ -39,7 +39,7 @@ keywords = [
     "matplotlib",
     "python",
 ]
-license = "BSD-3.0"
+license = "BSD-3-Clause"
 license-files = ["LICENSE"]
 readme = "README.md"
 requires-python = ">=3.9"
