Update license metadata for PEP 639

Author: lpsinger

pyproject.toml

@@ -1,11 +1,11 @@
 [build-system]
-requires = ["setuptools>=64", "setuptools_scm>=8"]
+requires = ["setuptools>=77", "setuptools_scm>=8"]
 build-backend = "setuptools.build_meta"
 
 [project]
 name = "gcn-kafka"
 description = "Kafka client for NASA's General Coordinates Network (GCN)"
-license = { text = "CC0-1.0" }
+license = "CC0-1.0"
 readme = "README.md"
 authors = [
     { name = "Leo Singer", email = "leo.p.singer@nasa.gov" },