Update .probo.yaml

.probo.yaml

@@ -2,6 +2,7 @@ steps:
   - plugin: Script
     name: Install NVM, Install dependencies, run tests
     script: |
+      npm -g install npm@latest
       NVM_PROFILE=/etc/profile.d/nvm.sh
       touch "${NVM_PROFILE}" 
       curl https://raw.githubusercontent.com/creationix/nvm/v0.32.1/install.sh -o install.sh