Update dependency ts-jest to v26.4.4

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
ts-jest (source)	devDependencies	patch	26.4.3 -> 26.4.4

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Release Notes

kulshekhar/ts-jest

### [`v26.4.4`](https://togithub.com/kulshekhar/ts-jest/blob/master/CHANGELOG.md#​2644-httpsgithubcomkulshekharts-jestcomparev2643v2644-2020-11-08) [Compare Source](https://togithub.com/kulshekhar/ts-jest/compare/v26.4.3...v26.4.4) ##### Bug Fixes - revert usage of `@jest/create-cache-key-function` ([#​2108](https://togithub.com/kulshekhar/ts-jest/issues/2108)) ([dee8231](https://togithub.com/kulshekhar/ts-jest/commit/dee823172ce1e8eb9e0b2dd3aeed1ab4033bd0d9)), closes [#​2080](https://togithub.com/kulshekhar/ts-jest/issues/2080) [#​2090](https://togithub.com/kulshekhar/ts-jest/issues/2090) [#​2104](https://togithub.com/kulshekhar/ts-jest/issues/2104) ##### Features - **testing:** expose all types for util `mocked` ([#​2096](https://togithub.com/kulshekhar/ts-jest/issues/2096)) ([b1d072b](https://togithub.com/kulshekhar/ts-jest/commit/b1d072b52b9a7665b3a6914b0895f84f6ee3f8c0)), closes [#​2086](https://togithub.com/kulshekhar/ts-jest/issues/2086)

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