chore: remove & check unused dependencies (#269)

`cargo shear` now passes

Author: branchseer

.github/workflows/ci.yml

@@ -71,9 +71,11 @@ jobs:
         with:
           save-cache: ${{ github.ref_name == 'main' }}
           cache-key: lint
+          tools: cargo-shear
           components: clippy rust-docs rustfmt
 
       - run: |
+          cargo shear
           cargo fmt --check
           # cargo clippy --all-targets --all-features -- -D warnings
           RUSTDOCFLAGS='-D warnings' cargo doc --no-deps --document-private-items