ci(travis): update to the latest npm

Author: trxcllnt

.travis.yml

@@ -25,7 +25,7 @@ before_install:
   - export PATH=$HOME/.yarn/bin:$PATH
   - which yarn # for debugging Travis
   - echo $PATH # for debugging Travis
-  - node -v && npm i -g npm@6.5.0 && npm -v
+  - node -v && npm i -g npm && npm -v
 
 script:
   - |