chore: fix gem spec

Author: michaellzc

.gitignore

@@ -7,6 +7,7 @@
 /spec/reports/
 /tmp/
 Gemfile.lock
+*.gem
 
 # rspec failure tracking
 .rspec_status

omniauth-open-edx.gemspec

@@ -12,8 +12,6 @@ Gem::Specification.new do |spec|
   spec.license = "MIT"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
 
-  spec.metadata["allowed_push_host"] = "TODO: Set to 'http://mygemserver.com'"
-
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] =
     "https://github.com/ibm-skills-network/omniauth-open-edx"