Drop Python 2.7 support on Windows
c_compiler: # [win]
- vs2017 # [win]
- vs2017 # [win]
- - vs2017 # [win]
cxx_compiler: # [win]
- vs2017 # [win]
- vs2017 # [win]
- - vs2017 # [win]
vc: # [win]
- 14.1 # [win]
- 14.1 # [win]
- - 14.1 # [win]
python: # [win]
- - 2.7 # [win]
- 3.6 # [win]
- 3.7 # [win]
