Update dependency autoprefixer to v8.6.3 (#192)

This Pull Request updates dependency [autoprefixer](https://github.com/postcss/autoprefixer) from `v8.6.2` to `v8.6.3`



<details>
<summary>Release Notes</summary>

### [`v8.6.3`](https://github.com/postcss/autoprefixer/blob/master/CHANGELOG.md#&#8203;863)
[Compare Source](postcss/autoprefixer@8.6.2...8.6.3)
* Add warnings for unsupported Grid features.
* Add warnings about wrong Grid properties.
* Add note about `grid` option for grid properties in `autoprefixer --info`.

---

</details>




---

This PR has been generated by [Renovate Bot](https://renovatebot.com).

package.json

@@ -15,7 +15,7 @@
     "@babel/preset-typescript": "7.0.0-beta.51",
     "@types/eslint": "4.16.2",
     "@types/jest": "23.1.0",
-    "autoprefixer": "8.6.2",
+    "autoprefixer": "8.6.3",
     "connect-history-api-fallback": "1.5.0",
     "cross-env": "5.2.0",
     "danger": "3.7.17",

yarn.lock

@@ -938,12 +938,12 @@ atob@^2.0.0:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/atob/-/atob-2.1.1.tgz#ae2d5a729477f289d60dd7f96a6314a22dd6c22a"
 
-autoprefixer@8.6.2:
-  version "8.6.2"
-  resolved "https://registry.yarnpkg.com/autoprefixer/-/autoprefixer-8.6.2.tgz#51d42ff13243820a582a53ecca20dedaeb7f2efd"
+autoprefixer@8.6.3:
+  version "8.6.3"
+  resolved "https://registry.yarnpkg.com/autoprefixer/-/autoprefixer-8.6.3.tgz#1d38a129e6a4582a565b6570d16f2d7d3de9cbf9"
   dependencies:
     browserslist "^3.2.8"
-    caniuse-lite "^1.0.30000851"
+    caniuse-lite "^1.0.30000856"
     normalize-range "^0.1.2"
     num2fraction "^1.2.2"
     postcss "^6.0.22"
@@ -1405,9 +1405,9 @@ caniuse-lite@^1.0.30000844, caniuse-lite@^1.0.30000846:
   version "1.0.30000846"
   resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000846.tgz#2092911eecad71a89dae1faa62bcc202fde7f959"
 
-caniuse-lite@^1.0.30000851:
-  version "1.0.30000851"
-  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000851.tgz#3b498aebf9f92cf6cff4ab54d13b557c0b590533"
+caniuse-lite@^1.0.30000856:
+  version "1.0.30000856"
+  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000856.tgz#ecc16978135a6f219b138991eb62009d25ee8daa"
 
 capture-exit@^1.2.0:
   version "1.2.0"