Bump ts-jest from 26.5.4 to 26.5.6

Bumps [ts-jest](https://github.com/kulshekhar/ts-jest) from 26.5.4 to 26.5.6.
- [Release notes](https://github.com/kulshekhar/ts-jest/releases)
- [Changelog](https://github.com/kulshekhar/ts-jest/blob/master/CHANGELOG.md)
- [Commits](kulshekhar/ts-jest@v26.5.4...v26.5.6)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -46,7 +46,7 @@
     "@zeit/ncc": "^0.22.3",
     "jest": "^26.6.3",
     "prettier": "^2.2.1",
-    "ts-jest": "^26.5.4",
+    "ts-jest": "^26.5.6",
     "typescript": "^4.2.4"
   }
 }