Update PyPI classifiers

Author: kislyuk

pyproject.toml

@@ -2,7 +2,7 @@
 name = "signxml"
 description = "Python XML Signature and XAdES library"
 readme = "README.rst"
-requires-python = ">=3.8"
+requires-python = ">=3.10"
 license = { text = "Apache Software License" }
 authors = [{ name = "Andrey Kislyuk"}, {email = "[email protected]" }]
 maintainers = [{ name = "Andrey Kislyuk"}, {email = "[email protected]" }]
@@ -14,12 +14,11 @@ classifiers = [
   "Operating System :: POSIX",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.8",
-  "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
+  "Programming Language :: Python :: 3.14",
   "Programming Language :: Python :: Implementation :: CPython",
   "Programming Language :: Python :: Implementation :: PyPy",
   "Development Status :: 5 - Production/Stable",