Dropped support of django 1.9, 1.10 and python 3.4

.travis.yml

 dist: xenial
 language: python
+
 python:
-  - 3.7.3
-  - 3.6
-  - 3.5
-  - 3.4
-  - 2.7
+  - "3.7"
+  - "3.6"
+  - "3.5"
+  - "2.7"
+
 env:
-  - DJANGO_VERSION=2.2.2
-  - DJANGO_VERSION=2.1.9
-  - DJANGO_VERSION=2.0.13
-  - DJANGO_VERSION=1.11.21
-  - DJANGO_VERSION=1.10.8
-  - DJANGO_VERSION=1.9.13
+  matrix:
+    - DJANGO=2.2
+    - DJANGO=2.1
+    - DJANGO=2.0
+    - DJANGO=1.11
+
 matrix:
+  include:
+    - env: STAGE=lint
+      python: "3.6"
   exclude:
-  - python: 3.4
-    env: DJANGO_VERSION=2.2.2
-  - python: 3.4
-    env: DJANGO_VERSION=2.1.9
-  - python: 2.7
-    env: DJANGO_VERSION=2.2.2
-  - python: 2.7
-    env: DJANGO_VERSION=2.1.9
-  - python: 2.7
-    env: DJANGO_VERSION=2.0.13
+    - python: "3.4"
+      env: DJANGO=2.2.2
+    - python: "3.4"
+      env: DJANGO=2.1.9
+    - python: "2.7"
+      env: DJANGO=2.2.2
+    - python: "2.7"
+      env: DJANGO=2.1.9
+    - python: "2.7"
+      env: DJANGO=2.0.13
+
 install:
-  - pip install -r dev-env-requirements.txt
-  - pip install django==$DJANGO_VERSION
-  - pip install codecov
+  - >
+    if [ -n "$DJANGO" ]; then
+      pip install -r dev-env-requirements.txt
+      pip install "django>=$DJANGO"
+      pip install codecov
+
+    elif [[ "$STAGE" == "lint" ]]; then
+      pip install flake8
+
+    fi
+
 script:
-  - ./setup.py test
+  - >
+    if [ -n "$DJANGO" ]; then
+      ./setup.py test
+
+    elif [[ "$STAGE" == "lint" ]]; then
+      flake8
+
+    fi
+
 after_success:
   - codecov
-jobs:
-  include:
-    - stage: lint
-      install:
-        - pip install flake8==3.7.7
-      script:
-        - flake8
-      after_success:
-    - stage: deploy
-      if: tag IS present
-      install: true
-      script: skip
-      after_success:
-      deploy:
-        provider: pypi
-        user: tfoxy-bot
-        password:
-          secure: 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
-        on:
-          tags: true
-stages:
-  - lint
-  - test
-  - deploy
+
+deploy:
+  provider: pypi
+  user: tfoxy-bot
+  password:
+    secure: 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
+  on:
+    tags: true