gnu: libyaml: Fix variable name for libyaml@0.2.

* gnu/packages/web.scm (libyaml-2.1): Rename to ...
(libyaml-0.2): ... this.
* gnu/packages/haskell-xyz.scm (ghc-libyaml)[inputs]: Adjust accordingly.

gnu/packages/haskell-xyz.scm

@@ -6628,7 +6628,7 @@ (define-public ghc-libyaml
     (inputs
      `(("ghc-conduit" ,ghc-conduit)
        ("ghc-resourcet" ,ghc-resourcet)
-       ("libyaml" ,libyaml-2.1)))
+       ("libyaml" ,libyaml-0.2)))
     (home-page "https://github.com/snoyberg/yaml#readme")
     (synopsis "Low-level, streaming YAML interface.")
     (description "This package provides a Haskell wrapper over the

gnu/packages/web.scm

@@ -1491,7 +1491,7 @@ (define-public libyaml
      "LibYAML is a YAML 1.1 parser and emitter written in C.")
     (license license:expat)))
 
-(define-public libyaml-2.1
+(define-public libyaml-0.2
   (package
     (inherit libyaml)
     (version "0.2.1")