Add source-map dependency (#4281)

package.json

@@ -91,6 +91,7 @@
     "recursive-copy": "2.0.6",
     "resolve": "1.5.0",
     "send": "0.16.1",
+    "source-map": "0.5.7",
     "strip-ansi": "3.0.1",
     "styled-jsx": "2.2.6",
     "touch": "3.1.0",

yarn.lock

@@ -6768,6 +6768,10 @@ source-map-url@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/source-map-url/-/source-map-url-0.4.0.tgz#3e935d7ddd73631b97659956d55128e87b5084a3"
 
+source-map@0.5.7, source-map@^0.5.0, source-map@^0.5.3, source-map@^0.5.6, source-map@^0.5.7, source-map@~0.5.1:
+  version "0.5.7"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
+
 source-map@0.6.1, source-map@^0.6.1, source-map@~0.6.1:
   version "0.6.1"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
@@ -6778,10 +6782,6 @@ source-map@^0.4.4:
   dependencies:
     amdefine ">=0.0.4"
 
-source-map@^0.5.0, source-map@^0.5.3, source-map@^0.5.6, source-map@^0.5.7, source-map@~0.5.1:
-  version "0.5.7"
-  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
-
 spawn-wrap@^1.3.8:
   version "1.4.2"
   resolved "https://registry.yarnpkg.com/spawn-wrap/-/spawn-wrap-1.4.2.tgz#cff58e73a8224617b6561abdc32586ea0c82248c"