chore: update Flow to 0.73 (#41)

Author: thymikee

.flowconfig

@@ -1,2 +1,2 @@
 [version]
-^0.66.0
+^0.73.0

package.json

@@ -31,7 +31,7 @@
     "babel-preset-react": "^6.24.1",
     "eslint": "^4.16.0",
     "eslint-config-callstack-io": "^1.1.1",
-    "flow-bin": "^0.66.0",
+    "flow-bin": "^0.73.0",
     "jest": "^22.0.6",
     "react": "^16.2.0",
     "react-test-renderer": "^16.2.0"

yarn.lock

@@ -1682,9 +1682,9 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flow-bin@^0.64.0:
-  version "0.64.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.64.0.tgz#ddd3fb3b183ab1ab35a5d5dec9caf5ebbcded167"
+flow-bin@^0.73.0:
+  version "0.73.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.73.0.tgz#da1b90a02b0ef9c439f068c2fc14968db83be425"
 
 for-in@^1.0.1:
   version "1.0.2"