Update dependency jest to v26 (#5884)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

package.json

@@ -80,7 +80,7 @@
     "eslint-plugin-prettier": "3.1.3",
     "eslint-plugin-react": "7.16.0",
     "fetch-mock": "9.4.0",
-    "jest": "25.5.3",
+    "jest": "26.0.1",
     "node-fetch": "2.6.0",
     "prettier": "2.0.5",
     "webpack-dev-server": "3.9.0"