chore(deps): bump lettre from 0.10.0 to 0.10.1 in /backend (#244)

Bumps [lettre](https://github.com/lettre/lettre) from 0.10.0 to 0.10.1.
- [Release notes](https://github.com/lettre/lettre/releases)
- [Changelog](https://github.com/lettre/lettre/blob/master/CHANGELOG.md)
- [Commits](https://github.com/lettre/lettre/compare/v0.10.0...v0.10.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

backend/Cargo.lock

@@ -1737,9 +1737,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "lettre"
-version = "0.10.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5677c78c7c7ede1dd68e8a7078012bc625449fb304e7b509b917eaaedfe6e849"
+checksum = "2eabca5e0b4d0e98e7f2243fb5b7520b6af2b65d8f87bcc86f2c75185a6ff243"
 dependencies = [
  "async-trait",
  "base64 0.13.0",