Use OTHER instead of Ruby in curations/gem/rubygems/-/unicorn.yaml

Due to wording difference between unicorn license and the official
Ruby license, the latter is not applicable here, according to SPDX
license matching guidelines.

Author: RomanIakovlev

curations/gem/rubygems/-/unicorn.yaml

@@ -5,10 +5,10 @@ coordinates:
 revisions:
   5.4.0:
     licensed:
-      declared: GPL-2.0-or-later OR Ruby
+      declared: GPL-2.0-or-later OR OTHER
   6.0.0:
     licensed:
-      declared: GPL-2.0-or-later OR Ruby
+      declared: GPL-2.0-or-later OR OTHER
   6.1.0:
     licensed:
-      declared: GPL-2.0-or-later OR Ruby
+      declared: GPL-2.0-or-later OR OTHER