Update dependency cssnano to v5.0.3

Author: renovate-bot

package.json

@@ -43,7 +43,7 @@
 		"create-pwa": "2.3.1",
 		"critical": "3.0.1",
 		"css-loader": "5.2.4",
-		"cssnano": "5.0.2",
+		"cssnano": "5.0.3",
 		"eslint": "7.26.0",
 		"eslint-config-recommended": "4.1.0",
 		"file-loader": "6.2.0",