Update dependency jest to v26

Author: renovate-bot

package.json

@@ -77,7 +77,7 @@
     "html-loader": "1.1.0",
     "html-webpack-plugin": "4.2.0",
     "husky": "4.2.5",
-    "jest": "25.3.0",
+    "jest": "26.4.0",
     "less": "3.11.1",
     "less-loader": "5.0.0",
     "lint-staged": "10.2.11",