Allow :npm-deps true

[mfikes]

The next release of ClojureScript will allow NPM deps to satisfy either map? or boolean?.

See https://github.com/clojure/clojurescript-site/pull/264/files

Currently, Figwheel complains if you put true:

The key :npm-deps at (:cljsbuild :builds 0 :compiler) has a non-conforming value: true
It should be a Map

  {:cljsbuild
   {:builds
    [{:compiler
      {:output-to "target/ios/index.js"
       :main "env.ios.main"
       :output-dir "target/ios"
       :optimizations :none
       :npm-deps true
       ^---- The value at key :npm-deps doesn't conform
       :target :nodejs}}]}}

[bhauman]

fixed