[fix] logilab-common requires python 3.6 now

setup.py

@@ -48,7 +48,7 @@ setup(
     classifiers=pkginfo["classifiers"],
     packages=find_packages(exclude=["contrib", "docs", "test*"]),
     namespace_packages=[pkginfo["subpackage_of"]],
-    python_requires=">=3.3",
+    python_requires=">=3.6",
     install_requires=pkginfo["install_requires"],
     tests_require=pkginfo["tests_require"],
     scripts=pkginfo["scripts"],