Update ignore files to remove shared tox.venv

.dockerignore

@@ -1,13 +1,12 @@
 # this file uses slightly different syntax than .gitignore,
-# e.g. "tox.cover/" will not ignore tox.cover directory
+# e.g. ".tox/" will not ignore .tox directory
 
 # well, official docker build should be done on clean git checkout
 # anyway, so .tox should be empty... But I'm sure people will try to
 # test docker on their git working directories.
 
 .git
-tox.venv
-tox.venv3
+.tox
 venv
 venv3
 docs

.gitignore

@@ -5,8 +5,6 @@ build/
 dist/
 /venv/
 /venv3/
-/tox.venv/
-/tox.venv/
 letsencrypt.log
 
 # coverage