fix model's on_cascade= parameter for test, update to latest gdal (#247)

.travis.yml

@@ -37,8 +37,9 @@ jobs:
       script: 'isort --check --diff'
 
 before_install: |
-  sudo apt update
-  sudo apt install binutils libproj-dev gdal-bin
+  sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable -y
+  sudo apt-get update
+  sudo apt-get install -y binutils libproj-dev gdal-bin
   pip install -U pip setuptools wheel
 install: |
   pip install -r ./dev-requirements.txt

test-data/typecheck/fields/test_related.yml

@@ -99,7 +99,7 @@
                 class User(models.Model):
                     pass
                 class Profile(models.Model):
-                    user = models.OneToOneField(to=User, on_delete=models)
+                    user = models.OneToOneField(to=User, on_delete=models.CASCADE)
 
 -   case: test_circular_dependency_in_imports_with_foreign_key
     main: |