uv-resolver: remove 'derive(Derivative)' from PubGrubPackage

It looks like the last vestiges of `Derivative` were removed in commit
7eaed07f6c, but the then rendered
superfluous `derive(Derivative)` wasn't removed.

crates/uv-resolver/src/pubgrub/package.rs

@@ -1,5 +1,3 @@
-use derivative::Derivative;
-
 use distribution_types::VerbatimParsedUrl;
 use uv_normalize::{ExtraName, PackageName};
 
@@ -12,8 +10,7 @@ use crate::resolver::Urls;
 /// 2. Uses the same strategy as pip and posy to handle extras: for each extra, we create a virtual
 ///    package (e.g., `black[colorama]`), and mark it as a dependency of the real package (e.g.,
 ///    `black`). We then discard the virtual packages at the end of the resolution process.
-#[derive(Debug, Clone, Eq, Derivative)]
-#[derivative(PartialEq, Hash)]
+#[derive(Debug, Clone, Eq, Hash, PartialEq)]
 pub enum PubGrubPackage {
     /// The root package, which is used to start the resolution process.
     Root(Option<PackageName>),