Assume npm 5.2.0 during development and CI

Author: novemberborn

.travis.yml

@@ -16,7 +16,7 @@ cache:
   directories:
     - $HOME/.npm
 before_install:
-  - npm install --global npm@^5.0.3
+  - npm install --global npm@^5.2.0
   - npm --version
   - if [[ ${FRESH_DEPS} == "true" ]]; then rm package-lock.json; fi
 install:

appveyor.yml

@@ -23,7 +23,7 @@ matrix:
       nodejs_version: 4
 install:
   - ps: Install-Product node $env:nodejs_version
-  - npm install --global npm@^5.0.3
+  - npm install --global npm@^5.2.0
   - npm --version
   - git config core.symlinks true
   - git reset --hard