build(deps): bump snafu-derive from 0.6.8 to 0.6.9

Bumps [snafu-derive](https://github.com/shepmaster/snafu) from 0.6.8 to 0.6.9.
- [Release notes](https://github.com/shepmaster/snafu/releases)
- [Changelog](https://github.com/shepmaster/snafu/blob/master/CHANGELOG.md)
- [Commits](https://github.com/shepmaster/snafu/compare/0.6.8...0.6.9)

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

Cargo.lock

@@ -1585,9 +1585,9 @@ dependencies = [
 
 [[package]]
 name = "snafu-derive"
-version = "0.6.8"
+version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebf8f7d5720104a9df0f7076a8682024e958bba0fe9848767bb44f251f3648e9"
+checksum = "7073448732a89f2f3e6581989106067f403d378faeafb4a50812eb814170d3e5"
 dependencies = [
  "proc-macro2",
  "quote",