Don't re-run tests on deployment

By the time we get to the deployment step, we've already run these tests
dozens of times. We don't need to run them yet again at deploy time.

.travis.yml

@@ -137,6 +137,8 @@ jobs:
         - poetry version "$TRAVIS_TAG"
         - echo __version__ = \"$TRAVIS_TAG\" > jrnl/__version__.py
         - poetry build
+      script:
+        - echo "Deployment starting..."
       deploy:
         - provider: script
           script: poetry publish