MAINT: cleanup license related deprecations

Author: bsipocz

setup.cfg

@@ -48,7 +48,7 @@ name = pyvo
 description = Astropy affiliated package for accessing Virtual Observatory data and services
 long_description = file: README.rst
 author = the PyVO Developers
-license = BSD
+license = BSD-3-Clause
 license_file = LICENSE.rst
 edit_on_github = False
 github_project = astropy/pyvo
@@ -57,14 +57,12 @@ project_urls =
     Documentation = https:/pyvo.readthedocs.io
 classifiers =
     Intended Audience :: Science/Research
-    License :: OSI Approved :: BSD License
     Operating System :: OS Independent
     Programming Language :: Python
     Programming Language :: Python :: 3
     Topic :: Database
     Topic :: Scientific/Engineering :: Astronomy
     Topic :: Software Development :: Libraries
-    License :: OSI Approved :: BSD License
 
 
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