[ci] Add setuptools as requirement to reframe

[victorusu]

No description provided.

[vkarak]

@jenkins-cscs retry daint

[vkarak]

lgtm

[teojgo]

for me it works when I create a virtual environment and use the requirements without setuptools

[vkarak]

@teojgo Yes, that's the norm, but there might be situation that setuptools are required. We had gone through this when preparing the official EB recipe for reframe.