Update LiteLLM default version for better SageMaker AI support

Author: bobbywlindsey

.env.template

@@ -1,6 +1,6 @@
 # LITELLM_VERSION eg: main-v1.56.5
 # Get it from https://github.com/berriai/litellm/pkgs/container/litellm/versions?filters%5Bversion_type%5D=tagged
-LITELLM_VERSION="litellm_stable_release_branch-v1.63.2-stable"
+LITELLM_VERSION="litellm_stable_release_branch-v1.73.0-stable"
 TERRAFORM_S3_BUCKET_NAME="" #Must be globally unique
 BUILD_FROM_SOURCE="false"
 HOSTED_ZONE_NAME=""