Update .travis.yml

.travis.yml

@@ -1,16 +1,13 @@
 language: python
 python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
   - "3.6"      # current default Python on Travis CI
   - "3.7"
   - "3.8"
   - "3.8-dev"  # 3.8 development branch
   - "nightly"  # nightly build
 # command to install dependencies
 install:
-  - pip install -r requirements.txt
+  - pip install PyPDF2==1.26.0
 # command to run tests
 script:
   - python setup.py || python3 setup.py