packaging: Fix license metadata (#553)

Author: edgarrmondragon

pyproject.toml

@@ -6,6 +6,9 @@ authors = [{ name = "Meltano Team and Contributors", email = "hello@meltano.com"
 requires-python = ">=3.9"
 readme = "README.md"
 license = "MIT"
+license-files = [
+    "LICENSE",
+]
 maintainers = [{ name = "Meltano Team and Contributors", email = "hello@meltano.com" }]
 keywords = [
     "Postgres",
@@ -16,7 +19,6 @@ keywords = [
 ]
 classifiers = [
     "Intended Audience :: Developers",
-    "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",