Update dependency rollup to v2.21.0

Author: renovate-bot

package.json

@@ -97,7 +97,7 @@
     "postcss-modules": "3.2.0",
     "prettier": "2.0.5",
     "rimraf": "3.0.2",
-    "rollup": "2.20.0",
+    "rollup": "2.21.0",
     "rollup-plugin-babel": "4.4.0",
     "rollup-plugin-commonjs": "10.1.0",
     "rollup-plugin-copy-assets": "2.0.1",

yarn.lock

@@ -13806,10 +13806,10 @@ rollup-pluginutils@^2.5.0, rollup-pluginutils@^2.6.0, rollup-pluginutils@^2.8.1,
   dependencies:
     estree-walker "^0.6.1"
 
-rollup@2.20.0:
-  version "2.20.0"
-  resolved "https://registry.yarnpkg.com/rollup/-/rollup-2.20.0.tgz#7456fed8424a5247954958751642e9fdd0ad7485"
-  integrity sha512-hkbp//ne1om8+PQRpd81zk0KDvbJxkLZdZJh1ZNxjd1EkI0H1TmYuHqqXx88yciS+5YnMom3geubQjTeeUnNNw==
+rollup@2.21.0:
+  version "2.21.0"
+  resolved "https://registry.yarnpkg.com/rollup/-/rollup-2.21.0.tgz#d2e114533812043d5c9b7b0a83f1b2a242e4e1d6"
+  integrity sha512-BEGgy+wSzux7Ycq58pRiWEOBZaXRXTuvzl1gsm7gqmsAHxkWf9nyA5V2LN9fGSHhhDQd0/C13iRzSh4bbIpWZQ==
   optionalDependencies:
     fsevents "~2.1.2"