Update virtue requirement from 0.0.17 to 0.0.18 (#731)

* Update virtue requirement from 0.0.17 to 0.0.18

Updates the requirements on [virtue](https://github.com/bincode-org/virtue) to permit the latest version.
- [Release notes](https://github.com/bincode-org/virtue/releases)
- [Commits](bincode-org/virtue@v0.0.17...v0.0.18)

---
updated-dependencies:
- dependency-name: virtue
  dependency-type: direct:production
...

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

* Fixed new lint warning

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Victor Koenders <github@trang.ar>

derive/Cargo.toml

@@ -19,4 +19,4 @@ description = "Implementation of #[derive(Encode, Decode)] for bincode"
 proc-macro = true
 
 [dependencies]
-virtue = "0.0.17"
+virtue = "0.0.18"

derive/src/derive_struct.rs

@@ -12,7 +12,7 @@ impl DeriveStruct {
     pub fn generate_encode(self, generator: &mut Generator) -> Result<()> {
         let crate_name = &self.attributes.crate_name;
         generator
-            .impl_for(&format!("{}::Encode", crate_name))
+            .impl_for(format!("{}::Encode", crate_name))
             .modify_generic_constraints(|generics, where_constraints| {
                 if let Some((bounds, lit)) =
                     (self.attributes.encode_bounds.as_ref()).or(self.attributes.bounds.as_ref())