Upgrade flow to 0.71.0 (#1330)

Author: kassens

.flowconfig

@@ -13,4 +13,4 @@ suppress_comment=\\(.\\|\n\\)*\\$FlowFixMe\\($\\|[^(]\\|(\\(<VERSION>\\)?)\\)
 suppress_comment=\\(.\\|\n\\)*\\$FlowIssue\\((\\(<VERSION>\\)?)\\)?:? #[0-9]+
 
 [version]
-^0.70.0
+^0.71.0

package.json

@@ -62,7 +62,7 @@
     "eslint-plugin-babel": "5.1.0",
     "eslint-plugin-flowtype": "2.46.3",
     "eslint-plugin-prettier": "2.6.0",
-    "flow-bin": "0.70.0",
+    "flow-bin": "0.71.0",
     "isparta": "4.0.0",
     "mocha": "5.1.1",
     "prettier": "1.12.1",

yarn.lock

@@ -1579,9 +1579,9 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flow-bin@0.70.0:
-  version "0.70.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.70.0.tgz#080ae83a997f2b4ddb3dc2649bf13336825292b5"
+flow-bin@0.71.0:
+  version "0.71.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.71.0.tgz#fd1b27a6458c3ebaa5cb811853182ed631918b70"
 
 for-in@^1.0.1, for-in@^1.0.2:
   version "1.0.2"