build(deps): bump lettre from 0.11.15 to 0.11.18

Bumps [lettre](https://github.com/lettre/lettre) from 0.11.15 to 0.11.18.
- [Release notes](https://github.com/lettre/lettre/releases)
- [Changelog](https://github.com/lettre/lettre/blob/master/CHANGELOG.md)
- [Commits](lettre/lettre@v0.11.15...v0.11.18)

---
updated-dependencies:
- dependency-name: lettre
  dependency-version: 0.11.18
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Cargo.lock

@@ -353,7 +353,7 @@ features = ["serde"]
 
 # Email sending
 [workspace.dependencies.lettre]
-version = "0.11.15"
+version = "0.11.18"
 default-features = false
 features = [
     "tokio1-rustls-tls",