Check that bin/cordova works on Travis CI (apache#343)

Ensure that bin script actually runs on current Node.js version
to detect and avoid bugs such as apache#339

Co-authored-by: Christopher J. Brody <chris.brody@gmail.com>
Co-authored-by: Jan Piotrowski <piotrowski+github@gmail.com>

.travis.yml

@@ -11,3 +11,9 @@ node_js:
   - "6"
   - "8"
   - "10"
+
+before_script:
+  # Ensure that bin script actually runs on used Node.js version
+  # to detect and avoid bugs such as apache/cordova-cli#339
+  # (<https://github.com/apache/cordova-cli/issues/339>)
+  - ./bin/cordova --version