Remove invalid input fields from CI action for Rust setup (#283)

Neither `override` nor `profile` are valid inputs for the
`dtolnay/rust-toolchain` action. It always uses the minimal
profile anyways.

.github/workflows/rust.yml

@@ -105,6 +105,4 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           toolchain: stable
-          override: true
-          profile: minimal
       - run: cargo doc --all-features