ci: don't install latest Node.js in deploy

Remove the `nvm install lts/*` line from the deploy script as the
default Node.js version _should_ be sufficient.

Author: Arcanemagus

.travis.yml

@@ -31,7 +31,6 @@ jobs:
         provider: script
         skip_cleanup: true
         script:
-          - nvm install lts/*
           - npx semantic-release
 
 ### Generic setup follows ###