Update dev dependencies (#2594)

* Update dev dependencies

.editorconfig

@@ -8,7 +8,7 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 indent_style = space
-indent_size = 1
+indent_size = 2
 
 # YAML
 [*.yml]

.eslintrc.json

@@ -16,6 +16,7 @@
         "singleQuote": true
       }
     ],
+    "require-atomic-updates": 0,
     "no-extra-semi": 0,
     "no-mixed-spaces-and-tabs": 0
   }

package.json

@@ -54,14 +54,14 @@
     "tag": "canary"
   },
   "devDependencies": {
-    "bluebird": "3.5.2",
-    "chai": "^4.1.2",
-    "chai-as-promised": "^7.1.1",
-    "clean-css-cli": "^4.1.11",
+    "bluebird": "3.5.5",
+    "chai": "4.2.0",
+    "chai-as-promised": "7.1.1",
+    "clean-css-cli": "4.3.0",
     "eclint": "^2.8.1",
-    "eslint": "^4.18.2",
-    "eslint-config-prettier": "^2.9.0",
-    "eslint-plugin-prettier": "^2.6.0",
+    "eslint": "6.2.2",
+    "eslint-config-prettier": "6.1.0",
+    "eslint-plugin-prettier": "3.1.0",
     "jsdoc": "^3.6.3",
     "license-checker": "^16.0.0",
     "mocha": "^5.0.4",