Update dependency rollup to v1.21.4

Author: renovate-bot

package.json

@@ -17,7 +17,7 @@
   },
   "devDependencies": {
     "prettier": "1.16.4",
-    "rollup": "1.20.3",
+    "rollup": "1.21.4",
     "rollup-plugin-node-resolve": "4.0.1"
   }
 }

yarn.lock

@@ -7,10 +7,10 @@
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
   integrity sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==
 
-"@types/node@^12.7.2":
-  version "12.7.2"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-12.7.2.tgz#c4e63af5e8823ce9cc3f0b34f7b998c2171f0c44"
-  integrity sha512-dyYO+f6ihZEtNPDcWNR1fkoTDf3zAK3lAABDze3mz6POyIercH0lEUawUFXlG8xaQZmm1yEBON/4TsYv/laDYg==
+"@types/node@^12.7.5":
+  version "12.7.5"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-12.7.5.tgz#e19436e7f8e9b4601005d73673b6dc4784ffcc2f"
+  integrity sha512-9fq4jZVhPNW8r+UYKnxF1e2HkDWOWKM5bC2/7c9wPV835I0aOrVbS/Hw/pWPk2uKrNXQqg9Z959Kz+IYDd5p3w==
 
 "@vaadin/[email protected]":
   version "1.4.2"
@@ -83,11 +83,11 @@ [email protected]:
     is-module "^1.0.0"
     resolve "^1.10.0"
 
-rollup@1.20.3:
-  version "1.20.3"
-  resolved "https://registry.yarnpkg.com/rollup/-/rollup-1.20.3.tgz#6243f6c118ca05f56b2d9433112400cd834a1eb8"
-  integrity sha512-/OMCkY0c6E8tleeVm4vQVDz24CkVgvueK3r8zTYu2AQNpjrcaPwO9hE+pWj5LTFrvvkaxt4MYIp2zha4y0lRvg==
+rollup@1.21.4:
+  version "1.21.4"
+  resolved "https://registry.yarnpkg.com/rollup/-/rollup-1.21.4.tgz#00a41a30f90095db890301b226cbe2918e4cf54d"
+  integrity sha512-Pl512XVCmVzgcBz5h/3Li4oTaoDcmpuFZ+kdhS/wLreALz//WuDAMfomD3QEYl84NkDu6Z6wV9twlcREb4qQsw==
   dependencies:
     "@types/estree" "0.0.39"
-    "@types/node" "^12.7.2"
+    "@types/node" "^12.7.5"
     acorn "^7.0.0"