guile_3_0: use correct version of guile for cross compilation

pkgs/development/interpreters/guile/3.0.nix

···
   depsBuildBuild = [
     buildPackages.stdenv.cc
   ] ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform)
-    pkgsBuildBuild.guile;
+    pkgsBuildBuild.guile_3_0;
   nativeBuildInputs = [
     makeWrapper
     pkg-config