debian: update minimum Python 3 version to >= 3.5

Support for Python 3.4 was dropped in the 0.12 release.

Author: indygreg

debian/control

@@ -15,7 +15,7 @@ Build-Depends:
   python3-setuptools
 Standards-Version: 3.9.1
 X-Python-Version: >=2.7
-X-Python3-Version: >= 3.4
+X-Python3-Version: >= 3.5
 Homepage: https://github.com/indygreg/python-zstandard
 Vcs-Browser: https://github.com/indygreg/python-zstandard.git
 Vcs-Git: https://github.com/indygreg/python-zstandard.git