Bookworm's setuptools chokes on the license setting in pyproject.toml. Remove it.

configuration error: `project.license` must be valid exactly by one definition (2 matches found)

--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,6 @@ version = "7.11"
 description="PostgreSQL Languages AST and statements prettifier"
 readme = "README.rst"
 authors = [{name = "Lele Gaifax", email = "lele@metapensiero.it"}]
-license = "GPL-3.0-or-later"
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Developers",
