fix: update pyproject.toml

Author: judithspd

pyproject.toml

@@ -18,7 +18,7 @@ classifiers = [
     "Intended Audience :: Science/Research",
     "License :: OSI Approved :: Apache Software License",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3 ",
+    "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",