fix(deps): update dependency source_gen to v4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
source_gen (source)	dependencies	major	^3.0.0 -> 4.1.1

---

Release Notes

dart-lang/source_gen (source_gen)

v4.1.1

Compare Source

• Allow analyzer: '>=8.1.1 <10.0.0'.

v4.1.0

Compare Source

• Add TypeChecker.typeNamedLiterally. It's like TypeChecker.typeNamed,
  but takes a String instead of a Type.

v4.0.2

Compare Source

• Bug fix: fix possible null pointer exception in TypeChecker.typeNamed on
  invalid code.

v4.0.1

Compare Source

• Require analyzer: '>=8.1.1 <9.0.0'.
• Allow build: '>=3.0.0 <5.0.0'.

v4.0.0

Compare Source

• Breaking Change: remove TypeChecker.fromRuntime, use
  TypeChecker.typeNamed instead. This removes all use of dart:mirror, so
  builders using source_gen can be AOT compiled for better performance.
• Keep // GENERATED FILE comments on the first line.

---

Configuration

📅 Schedule: Branch creation - "after 9pm,before 6am" in timezone Africa/Johannesburg, Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.