chore: Rename tox "flake8" env to "pep8"

This change will make marconi tox more compatible with other OSS projects,
so that folks can reuse their standard build scripts.

Author: kgriffs

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py26,py27,py33,pypy,flake8
+envlist = py26,py27,py33,pypy,pep8
 
 [testenv]
 deps = -r{toxinidir}/tools/test-requires
@@ -20,7 +20,7 @@ commands = {toxinidir}/tools/clean_cythoned.sh {toxinidir}/falcon
 deps = py3kwarn
 commands = py3kwarn falcon
 
-[testenv:flake8]
+[testenv:pep8]
 deps = flake8
 commands = flake8 \
            --max-complexity=12 \