Update .travis.yml to use poetry for build

.travis.yml

@@ -2,7 +2,7 @@ language: python
 os: linux
 dist: xenial
 python:
-    - '3.5'
+    - '3.6.8'
 cache:
     pip: true
     ccache: true
@@ -40,7 +40,7 @@ addons:
             - cython3
             - ccache
 install:
-    - pip install pipenv pysdl2 python-bitcoinrpc protobuf
+    - pip install pipenv pysdl2 python-bitcoinrpc protobuf poetry
     # From trezor-mcu to get the correct protobuf version
     - curl -LO "https://github.com/google/protobuf/releases/download/v3.4.0/protoc-3.4.0-linux-x86_64.zip"
     - unzip "protoc-3.4.0-linux-x86_64.zip" -d protoc
@@ -48,10 +48,10 @@ install:
     # Build emulators/simulators and bitcoind
     - cd test; ./setup_environment.sh; cd ..
     - pip uninstall -y trezor # Hack to get rid of master branch version of trezor that is installed for trezor-mcu build
-    - python setup.py install
+    - poetry install
 jobs:
     include:
         -   name: With process_commands interface
-            script: cd test; ./run_tests.py --interface=library
+            script: cd test; poetry run ./run_tests.py --interface=library
         -   name: With command line interface
-            script: cd test; ./run_tests.py --interface=cli
+            script: cd test; poetry run ./run_tests.py --interface=cli