Remove record from .gitignore (#269)

There is no usage of `omnibus/shards-darwin-*` in the project (anymore).

Author: miry

.gitignore

@@ -2,7 +2,6 @@ omnibus/pkg/
 omnibus/.bundle
 omnibus/bin
 omnibus/crystal-darwin-*
-omnibus/shards-darwin-*
 omnibus/vendor
 
 docs/build/