gnu: Remove ocaml-craml.

The package doesn't build from source and is unmaintained according to its
maintainer:
https://github.com/realworldocaml/craml/pull/8#issuecomment-529235628.

* gnu/packages/ocaml.scm (ocaml-craml): Delete variable.

gnu/packages/ocaml.scm

@@ -5049,39 +5049,6 @@ yojson package.  The program @code{atdgen} can be used to derive OCaml-JSON
 serializers and deserializers from type definitions.")
     (license license:bsd-3)))
  
-(define-public ocaml-craml
-  (package
-    (name "ocaml-craml")
-    (version "1.0.0")
-    (home-page "https://github.com/realworldocaml/craml")
-    (source
-     (origin
-       (method git-fetch)
-       (uri (git-reference
-             (url (string-append home-page ".git"))
-             (commit version)))
-       (file-name (git-file-name name version))
-       (sha256
-        (base32
-         "197xjp4vmzdymf2ndinw271ihpf45h04mx8gqj8ypspxdr5fj1a5"))))
-    (build-system dune-build-system)
-    (arguments
-     `(#:phases
-       (modify-phases %standard-phases
-         (add-before 'build 'upgrade
-           (lambda _
-             (invoke "dune" "upgrade")
-             #t)))))
-    (inputs
-     (list ocaml-fmt ocaml-astring ocaml-logs ocaml-cmdliner))
-    (synopsis
-     "CRAM-testing framework for testing command line applications")
-    (description "CRAM is a is functional testing framework for command line
-applications.  @code{craml} is freely inspired by the
-Mercurial's @code{https://www.selenic.com/blog/?p=663, unified test
-format}.  @code{craml} is released as a single binary (called @code{craml}).")
-    (license license:isc)))
-
 (define-public ocaml-merlin-lib
   (package
     (name "ocaml-merlin-lib")