Update dependency ts-jest to v26.5.6

Author: renovate-bot

package-lock.json

@@ -46,7 +46,7 @@
     "puppeteer": "7.1.0",
     "raw-loader": "4.0.1",
     "static-server": "2.2.1",
-    "ts-jest": "26.5.1",
+    "ts-jest": "26.5.6",
     "ts-loader": "7.0.0",
     "ts-node": "8.8.2",
     "tslint": "6.1.1",