Upgrade flow to 0.50 (jestjs#4036)

Author: SimenB

.flowconfig

@@ -13,4 +13,4 @@ module.name_mapper='^types/\(.*\)$' -> '<PROJECT_ROOT>/types/\1.js'
 module.name_mapper='\(jest-[^/]*\)' -> '<PROJECT_ROOT>/packages/\1/src/index.js'
 
 [version]
-^0.48.0
+^0.50.0

package.json

@@ -32,7 +32,7 @@
     "eslint-plugin-prettier": "^2.1.2",
     "eslint-plugin-react": "^7.1.0",
     "eslint-plugin-unicorn": "^2.1.2",
-    "flow-bin": "^0.48.0",
+    "flow-bin": "^0.50.0",
     "glob": "^7.1.1",
     "graceful-fs": "^4.1.11",
     "immutable": "^4.0.0-rc.1",

yarn.lock

@@ -2625,9 +2625,9 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flow-bin@^0.48.0:
-  version "0.48.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.48.0.tgz#72d075143524358db8901525e3c784dc13a7c7ee"
+flow-bin@^0.50.0:
+  version "0.50.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.50.0.tgz#d4cdb2430dee1a3599f0eb6fe551146e3027256a"
 
 flow-remove-types@^1.1.0:
   version "1.2.1"