chore(deps): update dev-dependency babel-loader to v8 (#12)

Author: renovate[bot]

package.json

@@ -50,7 +50,7 @@
     "babel-core": "^6.26.3",
     "babel-eslint": "^10.0.1",
     "babel-jest": "^22.4.4",
-    "babel-loader": "^7.1.5",
+    "babel-loader": "^8.0.4",
     "babel-plugin-external-helpers": "^6.22.0",
     "babel-plugin-transform-object-rest-spread": "^6.26.0",
     "babel-plugin-transform-runtime": "^6.23.0",

yarn.lock

@@ -686,14 +686,15 @@ babel-jest@^22.4.4:
     babel-plugin-istanbul "^4.1.5"
     babel-preset-jest "^22.4.4"
 
-babel-loader@^7.1.5:
-  version "7.1.5"
-  resolved "https://registry.yarnpkg.com/babel-loader/-/babel-loader-7.1.5.tgz#e3ee0cd7394aa557e013b02d3e492bfd07aa6d68"
-  integrity sha512-iCHfbieL5d1LfOQeeVJEUyD9rTwBcP/fcEbRCfempxTDuqrKpu0AZjLAQHEQa3Yqyj9ORKe2iHfoj4rHLf7xpw==
+babel-loader@^8.0.4:
+  version "8.0.4"
+  resolved "https://registry.yarnpkg.com/babel-loader/-/babel-loader-8.0.4.tgz#7bbf20cbe4560629e2e41534147692d3fecbdce6"
+  integrity sha512-fhBhNkUToJcW9nV46v8w87AJOwAJDz84c1CL57n3Stj73FANM/b9TbCUK4YhdOwEyZ+OxhYpdeZDNzSI29Firw==
   dependencies:
     find-cache-dir "^1.0.0"
     loader-utils "^1.0.2"
     mkdirp "^0.5.1"
+    util.promisify "^1.0.0"
 
 babel-messages@^6.23.0:
   version "6.23.0"