ci: fix travis build configuration warnings

Author: goto-bus-stop

.travis.yml

@@ -1,5 +1,6 @@
 language: node_js
 os: linux
+dist: xenial
 node_js:
   - "14"
   - "13"
@@ -21,7 +22,6 @@ before_install:
   - 'nvm install-latest-npm'
 install:
   - 'if [ "${TRAVIS_NODE_VERSION}" = "0.6" ] || [ "${TRAVIS_NODE_VERSION}" = "0.9" ]; then nvm install --latest-npm 0.8 && npm install && nvm use "${TRAVIS_NODE_VERSION}"; else npm install; fi;'
-sudo: false
 matrix:
   fast_finish: true
   allow_failures: