Bump strum from 0.19.5 to 0.20.0

Bumps [strum](https://github.com/Peternator7/strum) from 0.19.5 to 0.20.0.
- [Release notes](https://github.com/Peternator7/strum/releases)
- [Changelog](https://github.com/Peternator7/strum/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Peternator7/strum/commits)

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

Cargo.toml

@@ -42,7 +42,7 @@ rand = "0.7"
 webbrowser = "0.5"
 clipboard = { version = "0.5", optional = true }
 url = "1.7"
-strum = "0.19.5"
+strum = "0.20.0"
 strum_macros = "0.19.4"
 libc = "0.2"
 regex = "1"