rosenthal: Add go-github-com-cespare-xxhash-v2.

* rosenthal/packages/golang.scm (go-github-com-cespare-xxhash-v2): New
variable.

rosenthal/packages/golang.scm

@@ -9,6 +9,29 @@
   #:use-module (guix packages)
   #:use-module (gnu packages golang))
 
+(define-public go-github-com-cespare-xxhash-v2
+  (package
+    (name "go-github-com-cespare-xxhash-v2")
+    (version "2.1.2")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/cespare/xxhash")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "1f3wyr9msnnz94szrkmnfps9wm40s5sp9i4ak0kl92zcrkmpy29a"))))
+    (build-system go-build-system)
+    (arguments
+     '(#:import-path "github.com/cespare/xxhash/v2"))
+    (home-page "https://github.com/cespare/xxhash")
+    (synopsis "Go implementation of the 64-bit xxHash algorithm (XXH64)")
+    (description
+     "This package provides @code{xxhash}, a Go implementation of the 64-bit
+@url{https://cyan4973.github.io/xxHash/,xxHash} algorithm, XXH64.")
+    (license license:expat)))
+
 (define-public go-github-com-gin-contrib-sse
   (package
     (name "go-github-com-gin-contrib-sse")