Use SPDX form of license

Author: StevenMaude

pyproject.toml

@@ -8,7 +8,7 @@ version = "2.1.1"
 requires-python = ">=3.10"
 description = "PDFTables.com Python API library."
 readme = "README.md"
-license = { text = "Apache License 2.0" }
+license = { text = "Apache-2.0" }
 keywords = ["pdf", "tables", "excel", "csv", "xml", "api"]
 authors = [ { name = "Cantabular Ltd", email = "hello@pdftables.com" } ]
 urls = { "Homepage" = "https://github.com/pdftables/python-pdftables-api" }