Use generic for ci

.travis.yml

@@ -1,12 +1,17 @@
 sudo: required
+language: generic
+
 services:
   - docker
+
 before_install:
   - curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
   - sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
   - sudo apt-get update
   - sudo apt-get -o Dpkg::Options::="--force-confnew" -y install docker-ce shellcheck
+
 install: true
+
 jobs:
   include:
     - stage: lint