ci: Exlicitly require a newer version of setuptools in requirements-dev.txt

This commit changes the approach to fix issue originally addressed in
8ee05ad (ci: Fix python 3.4 windows build updating version of setuptools).

Author: jcfr

requirements-dev.txt

@@ -7,7 +7,7 @@ pytest-cov>=2.4.0
 pytest-runner>=2.9
 pytest-virtualenv>=1.2.5
 scikit-build>=0.7.1
-setuptools
+setuptools>=28.0.0
 twine
 virtualenv>=15.0.3
 wheel

scikit-ci.yml

@@ -24,7 +24,6 @@ install:
   commands:
     - python -c "import sys; print(sys.version)"
     - python -m pip install --disable-pip-version-check --upgrade pip
-    - pip install -U setuptools
     - pip install -U -r requirements-dev.txt
 
 before_build: