[bundler/bundler] Remove unnecessary test filter

Since it covers the whole range we support.

https://github.com/bundler/bundler/commit/c0b9d4e6c6

spec/bundler/commands/info_spec.rb

@@ -104,7 +104,7 @@ RSpec.describe "bundle info" do
       expect(out).to include("foo (1.0 #{sha[0..6]})")
     end
 
-    it "handles when a version is a '-' prerelease", :rubygems => "2.1" do
+    it "handles when a version is a '-' prerelease" do
       @git = build_git("foo", "1.0.0-beta.1", :path => lib_path("foo"))
       install_gemfile <<-G
         gem "foo", "1.0.0-beta.1", :git => "#{lib_path("foo")}"