gnu: diffoscope: Remove redundant let binding.

* gnu/packages/diffoscope.scm (diffoscope): Unbind VERSION.

gnu/packages/diffoscope.scm

@@ -70,10 +70,9 @@
   #:use-module (ice-9 match))
 
 (define-public diffoscope
-  (let ((version "145"))
   (package
     (name "diffoscope")
-      (version version)
+    (version "145")
     (source (origin
               (method git-fetch)
               (uri (git-reference
@@ -234,7 +233,7 @@ compare two tarballs, ISO images, or PDFs just as easily.
 Diffoscope has many optional dependencies; @code{diffoscope
 --list-missing-tools guix} will display optional packages to
 install.")
-      (license license:gpl3+))))
+    (license license:gpl3+)))
 
 (define-public reprotest
   (package