add requirements.txt file listing required packages

.gitattributes

@@ -9,3 +9,4 @@ dataset_description.json annex.largefiles=nothing
 highspeed-bids.Rproj annex.largefiles=nothing
 LICENSE annex.largefiles=nothing
 datacite.yml annex.largefiles=nothing
+requirements.txt annex.largefiles=nothing

requirements.txt

@@ -0,0 +1,21 @@
+appnope==0.1.0
+backcall==0.2.0
+decorator==4.4.2
+ipykernel==5.3.4
+ipython==7.18.1
+ipython-genutils==0.2.0
+jedi==0.17.2
+jupyter-client==6.1.7
+jupyter-core==4.6.3
+parso==0.7.1
+pexpect==4.8.0
+pickleshare==0.7.5
+prompt-toolkit==3.0.7
+ptyprocess==0.6.0
+Pygments==2.7.1
+python-dateutil==2.8.1
+pyzmq==19.0.2
+six==1.15.0
+tornado==6.0.4
+traitlets==5.0.4
+wcwidth==0.2.5