setup: pin click version for python2

.travis.yml

@@ -45,9 +45,12 @@ matrix:
 before_install:
   - travis_retry pip install --upgrade pip setuptools py
   - travis_retry pip install twine wheel coveralls requirements-builder
+  # requirements-builder in python2 only works with click<=7.0
+  - travis_retry pip install click==7.0
   - requirements-builder -e $EXTRAS --level=min setup.py > .travis-lowest-requirements.txt
   - requirements-builder -e $EXTRAS --level=pypi setup.py > .travis-release-requirements.txt
   - requirements-builder -e $EXTRAS --level=dev --req requirements-dev.txt setup.py > .travis-devel-requirements.txt
+  - travis_retry pip uninstall click -y
 
 install:
   - pip install -r requirements-dev.txt

reana_client/cli/workflow.py

@@ -995,7 +995,7 @@ def print_color_diff(lines):
             if not nonempty_sections:
                 click.secho('{} No differences in REANA specifications.'
                             .format(leading_mark), bold=True, fg='yellow')
-            # Rewrite section name workflow -> specification
+            # Rename section workflow -> specification
             if 'workflow' in nonempty_sections:
                 nonempty_sections['specification'] = \
                     nonempty_sections.pop('workflow')

setup.py

@@ -44,12 +44,13 @@
 install_requires = [
     'PyYAML>=5.1',
     'typing>=3.7.4 ; python_version=="2.7"',  # workaround for CWL deps
-    'click>=7',
+    'click>=7 ; python_version>="3"',
+    'click==7.0 ; python_version=="2.7"',
     'cryptography>=2.7',
     'cwltool==1.0.20191022103248',
     'pyOpenSSL>=19.0.0',  # FIXME remove once yadage-schemas solves deps.
     'jsonpointer>=2.0',
-    'reana-commons>=0.7.0.dev20200226,<0.8.0',
+    'reana-commons>=0.7.0.dev20200319,<0.8.0',
     'rfc3987>=1.3.8',  # FIXME remove once yadage-schemas solves deps.
     'six==1.12.0',
     'strict-rfc3339>=0.7',  # FIXME remove once yadage-schemas solves deps.