add ipython as requirements

Author: giannisdoukas

.travis.yml

@@ -12,6 +12,7 @@ before_install:
 install:
   - pip install -r test-requirements.txt
   - python setup.py install
+  - pip freeze
 script:
   - pycodestyle --max-line-length=119 $(find ipython2cwl -name '*.py')
   - coverage run --source ipython2cwl -m unittest discover tests

setup.py

@@ -59,7 +59,8 @@ def get_version(rel_path):
         'PyYAML>=5.3.1',
         'gitpython>=3.1.3',
         'jupyter-repo2docker>=0.11.0',
-        'nbconvert==5.6.1'
+        'nbconvert==5.6.1',
+        'ipython>=7.15.0'
     ],
     test_suite='tests',
 )