Update dependency query-string to v6.8.1

package.json

@@ -52,7 +52,7 @@
     "numeral": "2.0.6",
     "popper.js": "1.15.0",
     "prop-types": "15.7.2",
-    "query-string": "6.7.0",
+    "query-string": "6.8.1",
     "react": "16.8.6",
     "react-day-picker": "7.3.0",
     "react-dom": "16.8.6",

yarn.lock

@@ -7481,10 +7481,10 @@ qs@~6.5.2:
   resolved "https://registry.yarnpkg.com/qs/-/qs-6.5.2.tgz#cb3ae806e8740444584ef154ce8ee98d403f3e36"
   integrity sha512-N5ZAX4/LxJmF+7wN74pUD6qAh9/wnvdQcjq9TZjevvXzSUo7bfmw91saqMjzGS2xq91/odN2dW/WOl7qQHNDGA==
 
-query-string@6.7.0:
-  version "6.7.0"
-  resolved "https://registry.yarnpkg.com/query-string/-/query-string-6.7.0.tgz#7e92bf8525140cf8c5ebf500f26716b0de5b7023"
-  integrity sha512-oQ01H1jrgDRbPq5SjtJF470S418GOrKkds+fpvAt6DQatHXl7bmkaJulHbTIM+QNGtoPpa8f5k9W3Zk50zXRPQ==
+query-string@6.8.1:
+  version "6.8.1"
+  resolved "https://registry.yarnpkg.com/query-string/-/query-string-6.8.1.tgz#62c54a7ef37d01b538c8fd56f95740c81d438a26"
+  integrity sha512-g6y0Lbq10a5pPQpjlFuojfMfV1Pd2Jw9h75ypiYPPia3Gcq2rgkKiIwbkS6JxH7c5f5u/B/sB+d13PU+g1eu4Q==
   dependencies:
     decode-uri-component "^0.2.0"
     split-on-first "^1.0.0"