Fix comma (#7)

Author: Daltz333

setup.py

@@ -18,7 +18,7 @@
     long_description=long_description,
     long_description_content_type="text/markdown",
     url="https://github.com/wpilibsuite/sphinxext-remoteliteralinclude",
-    install_requires = ['sphinx>=2.0']
+    install_requires = ['sphinx>=2.0'],
     packages=['sphinxext'],
     classifiers=[
         'Development Status :: 5 - Production/Stable',