Bring back redis-namespace onto a gem release

Was running master because Ruby 3.0 wasn't working in 1.8.0

Gemfile

@@ -3,7 +3,7 @@ source "https://rubygems.org"
 gemspec
 
 gem "rake"
-gem "redis-namespace", github: "resque/redis-namespace", branch: :master
+gem "redis-namespace"
 gem "rails", ">= 6.0.2"
 gem "sqlite3", platforms: :ruby
 gem "activerecord-jdbcsqlite3-adapter", platforms: :jruby

Gemfile.lock

@@ -1,11 +1,3 @@
-GIT
-  remote: https://github.com/resque/redis-namespace.git
-  revision: 6f1bb31bbddd2efc9e16c53759d986b29206a12e
-  branch: master
-  specs:
-    redis-namespace (1.8.1)
-      redis (>= 3.0.4)
-
 PATH
   remote: .
   specs:
@@ -163,6 +155,8 @@ GEM
     rainbow (3.0.0)
     rake (13.0.6)
     redis (4.2.5)
+    redis-namespace (1.8.1)
+      redis (>= 3.0.4)
     regexp_parser (2.2.0)
     rexml (3.2.5)
     rubocop (1.24.1)
@@ -221,7 +215,7 @@ DEPENDENCIES
   net-smtp
   rails (>= 6.0.2)
   rake
-  redis-namespace!
+  redis-namespace
   sidekiq!
   simplecov
   sqlite3