I've just recently resolved this same deprecation in another addon simply by upgrading ember, and found this one now as well.
DEPRECATION: An addon is trying to access project.nodeModulesPath. This is not a reliable way to discover npm modules. Instead, consider doing: require("resolve").sync(something, { basedir: project.root }). Accessed from: new NPMDependencyVersionChecker (/home/skidder/dev/brokermate/node_modules/ember-component-inbound-actions/node_modules/ember-cli-version-checker/src/npm-dependency-version-checker.js:11:33)
I've just recently resolved this same deprecation in another addon simply by upgrading ember, and found this one now as well.
DEPRECATION: An addon is trying to access project.nodeModulesPath. This is not a reliable way to discover npm modules. Instead, consider doing: require("resolve").sync(something, { basedir: project.root }). Accessed from: new NPMDependencyVersionChecker (/home/skidder/dev/brokermate/node_modules/ember-component-inbound-actions/node_modules/ember-cli-version-checker/src/npm-dependency-version-checker.js:11:33)