setup.py: exclude versions of setuptools_scm due to pypa/setuptools-scm#109

since setuptools_scm 1.13.1, untracked files cause a dirty state; this makes auto deployment to PyPI fail where it worked before.
The issue has been fixed, but the new version of setuptools_scm has not been published yet.
So here we exclude the last two versions where this issue occurs.

Author: Cosimo Lupo

setup.py

@@ -21,7 +21,7 @@
     package_dir={"": "Lib"},
     packages=find_packages("Lib"),
     setup_requires=[
-        "setuptools_scm>=1.11.1",
+        "setuptools_scm>=1.11.1,!=1.13.1,!=1.14.0",
     ] + pytest_runner + wheel,
     tests_require=[
         'pytest>=3.0.2',