don't downgrade pip on windows wheel building (#190)

.azure-pipelines/wheel-builder.yml

@@ -152,8 +152,6 @@
                   PYTHON_VERSION: '38'
                   WINDOWS_ARCH: 'x86_64'
       steps:
-          - script: '"C:/Python%PYTHON_VERSION%/python.exe" -m pip install -U pip==10.0.1'
-            displayName: Downgrade pip lol
           - script: '"C:/Python%PYTHON_VERSION%/Scripts/pip" install wheel cffi six'
             displayName: Install wheel and our Python dependencies
           - script: |