👷 Fixes for truffleruby & jruby

Author: pboling

spec/oauth2/strategy/assertion_spec.rb

@@ -128,8 +128,8 @@
           it "raises JWT::EncodeError" do
             # this behavior is handled by the JWT gem, but this should make sure it is consistent
             # On old Ruby (versions 2.4 and below) the error raised was different because
-            #   a very old version of the jwt gem gets installed.
-            if VersionGem::Ruby.gte_minimum_version?("2.5")
+            #   an old version (< v2.4) of the jwt gem gets installed.
+            if Gem::Version.new(JWT::VERSION) >= Gem::Version.new("2.4")
               expect { client_assertion.get_token(claims, encoding_opts) }.to raise_error(JWT::EncodeError, "Unsupported signing method")
             else
               expect { client_assertion.get_token(claims, encoding_opts) }.to raise_error(NotImplementedError)