Update to rust 1.84.

This is the latest stable rust toolchain.
I had to run `cargo update` as some of the older
deps did not support latest rust.

I noticed a dependabot PR failed regarding a rust version mismatch:
#391

I'm not sure this will fix it, but it seems like a good step anyways.

Author: rcorre

Diff for: .github/workflows/rust.yml

@@ -24,7 +24,7 @@ jobs:
       uses: actions-rs/toolchain@v1
       with:
         profile: minimal
-        toolchain: 1.73.0
+        toolchain: 1.84.0
         override: true
         components: rustfmt, clippy