fix: Mark DMMF as deep readonly

[franky47]

Closes #97.

[github-actions[bot]]

Pull Request Test Coverage Report for Build 7807209062

• 0 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 80.727%

---

Totals
Change from base Build 7307786289:	0.0%
Covered Lines:	245
Relevant Lines:	290

---

💛 - Coveralls

[github-actions[bot]]

:tada: This PR is included in version 1.5.2-beta.1 :tada:

The release is available on:

• npm package (@beta dist-tag)
• GitHub release

Your semantic-release bot :package::rocket:

[github-actions[bot]]

:tada: This PR is included in version 1.5.2 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: