Use npm ci to install node modules

We also stop caching node_modules
because `npm ci` always starts from nothing
and will delete it if it is present.

.travis.yml

@@ -27,7 +27,6 @@ addons:
 
 cache:
   directories:
-    - launcher/node_modules
     - libs/_protobuf-install
 
 env:
@@ -39,6 +38,6 @@ before_install:
 
 install:
   - nvm install 10
-  - cd launcher && npm install && cd ..
+  - cd launcher && npm ci && cd ..
 
 script: ./travis.bash

appveyor.bat

@@ -4,7 +4,7 @@ echo node version || goto :error
 CALL node --version || goto :error
 echo npm version || goto :error
 CALL npm --version || goto :error
-CALL npm install || goto :error
+CALL npm ci || goto :error
 CALL npm run package || goto :error
 cd .. || goto :error
 

appveyor.yml

@@ -26,5 +26,4 @@ matrix:
   fast_finish: true
 
 cache:
-  - launcher\node_modules
   - libs\_protobuf-install