Update to assistants v2 everywhere

Author: alexrudall

lib/openai/batches.rb

@@ -1,7 +1,7 @@
 module OpenAI
   class Batches
     def initialize(client:)
-      @client = client.beta(assistants: "v1")
+      @client = client.beta(assistants: "v2")
     end
 
     def list

lib/openai/messages.rb

@@ -1,7 +1,7 @@
 module OpenAI
   class Messages
     def initialize(client:)
-      @client = client.beta(assistants: "v1")
+      @client = client.beta(assistants: "v2")
     end
 
     def list(thread_id:, parameters: {})

lib/openai/run_steps.rb

@@ -1,7 +1,7 @@
 module OpenAI
   class RunSteps
     def initialize(client:)
-      @client = client.beta(assistants: "v1")
+      @client = client.beta(assistants: "v2")
     end
 
     def list(thread_id:, run_id:, parameters: {})

lib/openai/runs.rb

@@ -1,7 +1,7 @@
 module OpenAI
   class Runs
     def initialize(client:)
-      @client = client.beta(assistants: "v1")
+      @client = client.beta(assistants: "v2")
     end
 
     def list(thread_id:, parameters: {})

lib/openai/threads.rb

@@ -1,7 +1,7 @@
 module OpenAI
   class Threads
     def initialize(client:)
-      @client = client.beta(assistants: "v1")
+      @client = client.beta(assistants: "v2")
     end
 
     def retrieve(id:)