Take up wagtail 2.11 in Travis test matrix and tox settings

.travis.yml

@@ -36,6 +36,8 @@ matrix:
       env: TOXENV=py36-django22-wagtail26-geoip2
     - python: 3.6
       env: TOXENV=py36-django111-wagtail22
+    - python: 3.6
+      env: TOXENV=py36-django22-wagtail211-geoip2
 
 install:
   - pip install tox codecov

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py{36}-django{111,20,21,22}-wagtail{20,21,22,23,24,25,26}{,-geoip2},lint
+envlist = py{36}-django{111,20,21,22}-wagtail{20,21,22,23,24,25,26,211}{,-geoip2},lint
 
 [testenv]
 basepython = python3.6
@@ -16,6 +16,7 @@ deps =
     wagtail24: wagtail>=2.4,<2.5
     wagtail25: wagtail>=2.5,<2.6
     wagtail26: wagtail>=2.6,<2.7
+    wagtail211: wagtail>=2.11,<2.12
     geoip2: geoip2
     django111: django>=1.11,<1.12