Update Flow to 0.75 + other deps (#1402)

* Update to Flow '0.75'

* Update deps

Author: IvanGoncharov

.flowconfig

@@ -13,4 +13,4 @@ suppress_comment=\\(.\\|\n\\)*\\$FlowFixMe\\($\\|[^(]\\|(\\(<VERSION>\\)?)\\)
 suppress_comment=\\(.\\|\n\\)*\\$FlowIssue\\((\\(<VERSION>\\)?)\\)?:? #[0-9]+
 
 [version]
-^0.73.0
+^0.75.0

package.json

@@ -48,34 +48,34 @@
     "iterall": "^1.2.2"
   },
   "devDependencies": {
-    "@babel/cli": "^7.0.0-beta.46",
-    "@babel/core": "^7.0.0-beta.46",
-    "@babel/node": "^7.0.0-beta.46",
-    "@babel/plugin-proposal-class-properties": "^7.0.0-beta.46",
-    "@babel/plugin-proposal-object-rest-spread": "^7.0.0-beta.46",
-    "@babel/plugin-syntax-async-generators": "^7.0.0-beta.46",
-    "@babel/plugin-transform-classes": "^7.0.0-beta.46",
-    "@babel/plugin-transform-destructuring": "^7.0.0-beta.46",
-    "@babel/plugin-transform-flow-strip-types": "^7.0.0-beta.46",
-    "@babel/plugin-transform-modules-commonjs": "^7.0.0-beta.46",
-    "@babel/plugin-transform-spread": "^7.0.0-beta.46",
-    "@babel/polyfill": "^7.0.0-beta.46",
-    "@babel/preset-env": "^7.0.0-beta.46",
-    "@babel/register": "^7.0.0-beta.46",
-    "babel-eslint": "8.2.3",
+    "@babel/cli": "^7.0.0-beta.51",
+    "@babel/core": "^7.0.0-beta.51",
+    "@babel/node": "^7.0.0-beta.51",
+    "@babel/plugin-proposal-class-properties": "^7.0.0-beta.51",
+    "@babel/plugin-proposal-object-rest-spread": "^7.0.0-beta.51",
+    "@babel/plugin-syntax-async-generators": "^7.0.0-beta.51",
+    "@babel/plugin-transform-classes": "^7.0.0-beta.51",
+    "@babel/plugin-transform-destructuring": "^7.0.0-beta.51",
+    "@babel/plugin-transform-flow-strip-types": "^7.0.0-beta.51",
+    "@babel/plugin-transform-modules-commonjs": "^7.0.0-beta.51",
+    "@babel/plugin-transform-spread": "^7.0.0-beta.51",
+    "@babel/polyfill": "^7.0.0-beta.51",
+    "@babel/preset-env": "^7.0.0-beta.51",
+    "@babel/register": "^7.0.0-beta.51",
+    "babel-eslint": "8.2.4",
     "babel-plugin-syntax-async-functions": "6.13.0",
     "beautify-benchmark": "0.2.4",
     "benchmark": "2.1.4",
     "chai": "4.1.2",
     "coveralls": "3.0.1",
     "eslint": "4.19.1",
     "eslint-plugin-babel": "5.1.0",
-    "eslint-plugin-flowtype": "2.48.0",
+    "eslint-plugin-flowtype": "2.49.3",
     "eslint-plugin-prettier": "2.6.0",
-    "flow-bin": "0.73.0",
+    "flow-bin": "0.75.0",
     "mocha": "5.2.0",
-    "nyc": "^11.8.0",
-    "prettier": "1.13.3",
+    "nyc": "^12.0.2",
+    "prettier": "1.13.5",
     "sane": "2.5.2"
   }
 }

src/jsutils/dedent.js

@@ -7,14 +7,18 @@
  * @flow strict
  */
 
+import invariant from './invariant';
+
 /**
  * fixes indentation by removing leading spaces and tabs from each line
  */
 function fixIndent(str: string): string {
   const trimmedStr = str
     .replace(/^\n*/m, '') //  remove leading newline
     .replace(/[ \t]*$/, ''); // remove trailing spaces and tabs
-  const indent = /^[ \t]*/.exec(trimmedStr)[0]; // figure out indent
+  const indentMatch = /^[ \t]*/.exec(trimmedStr);
+  invariant(Array.isArray(indentMatch));
+  const indent = indentMatch[0]; // figure out indent
   return trimmedStr.replace(RegExp('^' + indent, 'mg'), ''); // remove indent
 }