Swift: Bump github.com/vapor/postgres-kit

Bumps the swift-dependencies group with 1 update: [github.com/vapor/postgres-kit](https://github.com/vapor/postgres-kit).


Updates `github.com/vapor/postgres-kit` from 2.13.3 to 2.13.4
- [Release notes](https://github.com/vapor/postgres-kit/releases)
- [Commits](vapor/postgres-kit@2.13.3...2.13.4)

---
updated-dependencies:
- dependency-name: github.com/vapor/postgres-kit
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: swift-dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]