gnu: Add rust-objc2-encode-3.

* gnu/packages/crates-io.scm (rust-objc2-encode-3): New variable.
(rust-objc2-encode-2): Inherit from rust-objc2-encode-3.

Change-Id: I7788193daa3b16efac5f4510ff91b5b43bcd84c0

gnu/packages/crates-io.scm

@@ -45755,8 +45755,27 @@ Foundation framework.")
 the Cocoa Foundation framework.")
     (license license:expat)))
 
+(define-public rust-objc2-encode-3
+  (package
+    (name "rust-objc2-encode")
+    (version "3.0.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "objc2-encode" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "0rknhkcnyj4qv1pzqp5j8l80726phz8fcxpsbpz9nhmg6xdq8yfh"))))
+    (build-system cargo-build-system)
+    (home-page "https://github.com/madsmtm/objc2")
+    (synopsis "Objective-C type-encoding representation and parsing")
+    (description "This package provides objective-C type-encoding
+representation and parsing.")
+    (license license:expat)))
+
 (define-public rust-objc2-encode-2
   (package
+    (inherit rust-objc2-encode-3)
     (name "rust-objc2-encode")
     (version "2.0.0-pre.2")
     (source (origin
@@ -45766,15 +45785,9 @@ the Cocoa Foundation framework.")
               (sha256
                (base32
                 "04h5wns3hxmc9g652hr9xqzrijs4ij9sdnlgc0ha202v050srz5b"))))
-    (build-system cargo-build-system)
     (arguments
      `(#:tests? #f      ; Test suite wants gcc-objc
-       #:cargo-inputs (("rust-objc-sys" ,rust-objc-sys-0.2))))
+       #:cargo-inputs (("rust-objc-sys" ,rust-objc-sys-0.2))))))
-    (home-page "https://github.com/madsmtm/objc2")
-    (synopsis "Objective-C type-encoding representation and parsing")
-    (description "This package provides objective-C type-encoding
-representation and parsing.")
-    (license license:expat)))
 
 (define-public rust-objc2-proc-macros-0.1
   (package