Change license type, add changelog ref

Author: clauspruefer

pyproject.toml

@@ -13,7 +13,7 @@ readme = "README.md"
 requires-python = ">=3.8"
 classifiers = [
     "Programming Language :: Python :: 3",
-    "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+    "License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)",
     "Operating System :: Microsoft :: Windows",
     "Operating System :: POSIX :: Linux"
 ]
@@ -22,3 +22,4 @@ classifiers = [
 Homepage = "https://github.com/clauspruefer/python-xml-microparser"
 Issues = "https://github.com/clauspruefer/python-xml-microparser/issues"
 Documentation = "https://pythondocs.webcodex.de/xml-microparser"
+Changelog = "https://github.com/clauspruefer/python-xml-microparser/CHANGELOG.md"