Bump regex from 1.1.6 to 1.7.0 in /workshop_serveless/ex5

Bumps [regex](https://github.com/rust-lang/regex) from 1.1.6 to 1.7.0.
- [Release notes](https://github.com/rust-lang/regex/releases)
- [Changelog](https://github.com/rust-lang/regex/blob/master/CHANGELOG.md)
- [Commits](rust-lang/regex@1.1.6...1.7.0)

---
updated-dependencies:
- dependency-name: regex
  dependency-type: indirect
...

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