gnu: guile: Remove version 2.0.13.

This package was unused since 0991fd5336.

* gnu/packages/guile.scm (guile-2.0.13): Remove.

gnu/packages/guile.scm

@@ -213,20 +213,6 @@ without requiring the source code to be rewritten.")
    (home-page "https://www.gnu.org/software/guile/")
    (license license:lgpl3+)))
 
-(define-public guile-2.0.13
-  ;; For testing a "minimal" Guix
-  (hidden-package
-   (package (inherit guile-2.0)
-     (name "guile")
-     (version "2.0.13")
-     (source (origin
-               (method url-fetch)
-               (uri (string-append "mirror://gnu/guile/guile-" version
-                                   ".tar.xz"))
-               (sha256
-                (base32
-                 "12yqkr974y91ylgw6jnmci2v90i90s7h9vxa4zk0sai8vjnz4i1p")))))))
-
 (define-public guile-2.2
   (package (inherit guile-2.0)
     (name "guile")