Update / add test dependencies to remove warnings

Running tests emitted some console warnings that were coming from test dependencies.

Fixed this by adding react-test-renderer and updating react-addons-test-utils.

See: facebook/create-react-app#1951

frontend/package.json

@@ -67,6 +67,7 @@
     "npm-run-all": "^4.1.2",
     "react-addons-test-utils": "^15.5.1",
     "react-scripts": "1.0.17",
+    "react-test-renderer": "^15.5.1",
     "stylelint": "^7.10.1",
     "stylelint-config-standard": "^16.0.0"
   },

frontend/yarn.lock

@@ -3164,18 +3164,6 @@ fbjs@^0.8.16, fbjs@^0.8.9:
     setimmediate "^1.0.5"
     ua-parser-js "^0.7.9"
 
-fbjs@^0.8.4:
-  version "0.8.12"
-  resolved "https://registry.yarnpkg.com/fbjs/-/fbjs-0.8.12.tgz#10b5d92f76d45575fd63a217d4ea02bea2f8ed04"
-  dependencies:
-    core-js "^1.0.0"
-    isomorphic-fetch "^2.1.1"
-    loose-envify "^1.0.0"
-    object-assign "^4.1.0"
-    promise "^7.1.1"
-    setimmediate "^1.0.5"
-    ua-parser-js "^0.7.9"
-
 figures@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/figures/-/figures-2.0.0.tgz#3ab1a2d2a62c8bfb431a0c94cb797a2fce27c962"
@@ -6491,11 +6479,8 @@ rc@^1.1.7:
     strip-json-comments "~2.0.1"
 
 react-addons-test-utils@^15.5.1:
-  version "15.5.1"
-  resolved "https://registry.yarnpkg.com/react-addons-test-utils/-/react-addons-test-utils-15.5.1.tgz#e0d258cda2a122ad0dff69f838260d0c3958f5f7"
-  dependencies:
-    fbjs "^0.8.4"
-    object-assign "^4.1.0"
+  version "15.6.2"
+  resolved "https://registry.yarnpkg.com/react-addons-test-utils/-/react-addons-test-utils-15.6.2.tgz#c12b6efdc2247c10da7b8770d185080a7b047156"
 
 react-axe@^2.1.1:
   version "2.1.4"
@@ -6740,6 +6725,13 @@ react-tabs@^2.1.0:
     classnames "^2.2.0"
     prop-types "^15.5.0"
 
+react-test-renderer@^15.5.1:
+  version "15.6.2"
+  resolved "https://registry.yarnpkg.com/react-test-renderer/-/react-test-renderer-15.6.2.tgz#d0333434fc2c438092696ca770da5ed48037efa8"
+  dependencies:
+    fbjs "^0.8.9"
+    object-assign "^4.1.0"
+
 react-transition-group@^2.2.0:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/react-transition-group/-/react-transition-group-2.2.1.tgz#e9fb677b79e6455fd391b03823afe84849df4a10"