Update dependency ts-jest to v26.4.3

Author: renovate-bot

package.json

@@ -37,7 +37,7 @@
     "@types/jest": "26.0.15",
     "jest": "26.6.1",
     "jest-fetch-mock": "3.0.3",
-    "ts-jest": "26.4.2",
+    "ts-jest": "26.4.3",
     "tslint": "6.1.3",
     "typedoc": "0.19.2",
     "typedoc-plugin-external-module-name": "4.0.3",