Added back docs requirements

docs/requirements.txt

@@ -0,0 +1,72 @@
+alabaster==0.7.13
+asdf==2.15.1
+asdf-astropy==0.4.0
+asdf-coordinates-schemas==0.2.0
+asdf-standard==1.0.3
+asdf-transform-schemas==0.3.0
+asdf-unit-schemas==0.1.0
+asdf-wcs-schemas==0.1.1
+astropy==5.3.2
+attrs==23.1.0
+Babel==2.12.1
+certifi==2023.7.22
+charset-normalizer==3.2.0
+colorama==0.4.6
+contourpy==1.1.0
+cycler==0.11.0
+docutils==0.18.1
+fonttools==4.42.1
+gwcs==0.18.3
+idna==3.4
+imagesize==1.4.1
+importlib-metadata==6.8.0
+importlib-resources==6.0.1
+Jinja2==3.1.2
+jmespath==1.0.1
+jsonschema==4.19.0
+jsonschema-specifications==2023.7.1
+kiwisolver==1.4.4
+livereload==2.6.3
+markdown-it-py==3.0.0
+MarkupSafe==2.1.3
+matplotlib==3.7.2
+mdit-py-plugins==0.4.0
+mdurl==0.1.2
+myst-parser==2.0.0
+ndcube==2.1.3
+numpy==1.25.2
+numpydoc==1.5.0
+packaging==23.1
+pandas==2.0.3
+Pillow==10.0.0
+pyerfa==2.0.0.3
+Pygments==2.16.1
+pyparsing==3.0.9
+python-dateutil==2.8.2
+pytz==2023.3
+PyYAML==6.0.1
+referencing==0.30.2
+requests==2.31.0
+rpds-py==0.9.2
+scipy==1.11.2
+semantic-version==2.10.0
+six==1.16.0
+snowballstemmer==2.2.0
+specutils==1.11.0
+Sphinx==7.2.2
+sphinx-autobuild==2021.3.14
+sphinx-automodapi==0.16.0
+sphinx-rtd-theme==1.3.0
+sphinxcontrib-applehelp==1.0.7
+sphinxcontrib-devhelp==1.0.5
+sphinxcontrib-htmlhelp==2.0.4
+sphinxcontrib-jquery==4.1
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-mermaid==0.9.2
+sphinxcontrib-qthelp==1.0.6
+sphinxcontrib-serializinghtml==1.1.9
+sphinxcontrib-websupport==1.2.6
+tornado==6.3.3
+tzdata==2023.3
+urllib3==2.0.4
+zipp==3.16.2