Update Angular-cli for Travis CI

[simison]

Perhaps this fixes failing Travis tests:

ng test
/home/travis/build/jameskleeh/angular-confirm/node_modules/@ngtools/json-schema/src/schema-class-factory.js:34
            result.push(...indices);
                        ^^^
SyntaxError: Unexpected token ...
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:373:25)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (/home/travis/build/jameskleeh/angular-confirm/node_modules/@ngtools/json-schema/src/index.js:3:30)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)