[Agent 1.1.2] Update version of the agent to 1.1.2

Why is this change needed?
---------
Prior to this change, Agent version was set to 1.1.1, so for the new release we need to set to 1.1.2

How does it address the issue?
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This change will update the patch version of the agent, for new release 1.1.2

Author: Anandaraju Coimbatore Sivaraju

codedeploy_agent.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |spec|
   spec.name          = 'aws_codedeploy_agent'
-  spec.version       = '1.1.1'
+  spec.version       = '1.1.2'
   spec.summary       = 'Packages AWS CodeDeploy agent libraries'
   spec.description   = 'AWS CodeDeploy agent is responsible for doing the actual work of deploying software on an individual EC2 instance'
   spec.author        = 'Amazon Web Services'