Codebuild Image aws/codebuild/standard:3.0 is soon to be unsupported

The codebuild image used to create the inline scanner currently (aws/codebuild/standard:3.0) will move to an unsupported status on June 20th, per an email we received from AWS.  This should probably be updated to use the standard:4.0 or standard:5.0 image in modules/infrastructure/codebuild/main.tf.