set official Django 2.2.x release into the Travis config file

.travis.yml

@@ -13,16 +13,16 @@ env:
 
   matrix:
     - DJANGO_VERSION="Django>=2.2,<2.3"
-    - DJANGO_VERSION='https://github.com/tmszi/django/archive/ticket_31000_stable_2.2.x.tar.gz'
+    - DJANGO_VERSION='https://github.com/django/django/archive/master.tar.gz'
 python:
   - "3.6"
 before_install:
   - sudo apt-get install -y python-gdal
 install:
-  - 
+  -
   - pip install pipenv
   - pipenv install --dev --ignore-pipfile
-  - pipenv run pip install flake8-strict  # not installable with pipenv, move ther when repaired
+  - pipenv run pip install flake8-strict # not installable with pipenv, move ther when repaired
   - pipenv run pip install -q $DJANGO_VERSION
 before_script:
   - npm install -g bower sass
@@ -41,5 +41,5 @@ after_script:
 addons:
   postgresql: "9.6"
 matrix:
-   allow_failures:
-      - env: DJANGO_VERSION='https://github.com/tmszi/django/archive/ticket_31000_stable_2.2.x.tar.gz'
+  allow_failures:
+    - env: DJANGO_VERSION='https://github.com/django/django/archive/master.tar.gz'