Problem solved by the enhancement

By accident Struson could depend on a future introduced by a version of a dependency newer than specified in Cargo.toml; users of Struson could then encounter build issues if Cargo's dependency resolution picks the older version (e.g. due to restrictions from other dependencies).

Enhancement description

Consider using Cargo's direct-minimal-versions or https://crates.io/crates/cargo-minimal-versions (or similar).

Alternatives / workarounds

• Include this as task in Makefile.toml instead of just in a GitHub workflow
  (maybe not worth it because it causes too much overhead for every build)
• Do nothing and hope / assume the problem described above is not common enough