Ignore unconditional_recursion clippy lint due to false positive

rust-lang/rust-clippy#12133

    warning: function cannot return without recursing
      --> gen/build/src/cargo.rs:91:5
       |
    91 | /     fn eq(&self, rhs: &Self) -> bool {
    92 | |         Lookup::new(&self.0).eq(Lookup::new(&rhs.0))
    93 | |     }
       | |_____^
       |
    note: recursive call site
      --> gen/build/src/cargo.rs:92:9
       |
    92 |         Lookup::new(&self.0).eq(Lookup::new(&rhs.0))
       |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unconditional_recursion
       = note: `-W clippy::unconditional-recursion` implied by `-W clippy::all`
       = help: to override `-W clippy::all` add `#[allow(clippy::unconditional_recursion)]`

Author: dtolnay

gen/build/src/lib.rs

@@ -76,6 +76,7 @@
     clippy::too_many_arguments,
     clippy::too_many_lines,
     clippy::toplevel_ref_arg,
+    clippy::unconditional_recursion, // clippy bug: https://github.com/rust-lang/rust-clippy/issues/12133
     clippy::uninlined_format_args,
     clippy::upper_case_acronyms,
     clippy::wrong_self_convention, // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6983