Update .travis.yml

Author: psykzz

.travis.yml

@@ -2,7 +2,7 @@ services: docker
 before_install:
   # set env vars in the build settings to interact with repositories
   # see https://docs.travis-ci.com/user/environment-variables/#Defining-Variables-in-Repository-Settings
-  - docker login -e="${DOCKER_EMAIL}" -u="${DOCKER_USERNAME}" -p="{$DOCKER_PASSWORD}"
+  - docker login -e="${DOCKER_EMAIL}" -u="${DOCKER_USERNAME}" -p="${DOCKER_PASSWORD}"
 script:
   - docker build -t "zopanix/factorio:${TRAVIS_TAG}" .
 deploy: