Bump rust from 1.54-buster to 1.60.0-buster (#173)

* Bump rust from 1.54-buster to 1.60.0-buster

Bumps rust from 1.54-buster to 1.60.0-buster.

---
updated-dependencies:
- dependency-name: rust
  dependency-type: direct:production
...

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

* fmt

* Remove examples

* Fix config test

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

src/main.rs

@@ -21,7 +21,7 @@ fn main() {
         .about("Send emails based on regular expressions")
         .args(&[
             Arg::with_name("config")
-                 .default_value("./config.yml")
+                .default_value("./config.yml")
                 .required(true)
                 .takes_value(true)
                 .short("c")