Add license information to pyproject.toml

Add license specifiers according to https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license-and-license-files

This allows automatic license inspection tools like pip-licenses to correctly categorize this package.

Author: ecederstrand

packages/google-crc32c/pyproject.toml

@@ -22,3 +22,5 @@ version = "1.8.0"
 description = "A python wrapper of the C library 'Google CRC32C'"
 readme = "README.md"
 requires-python = ">=3.8"
+license = "Apache-2.0"
+license-files = ["LICENSE"]