Back off desync_mitigation_mode to defensive

Setting desync_mitigation_mode to strictest breaks clients that
aren't strictly RFC 7230 compliant (notably, AWS API Gateway).
Setting this attribute to defensive provides sufficent protection
against desync attacks, while still allowing requests from clients
that we can't perfect.
https://en.wikipedia.org/wiki/Robustness_principle

Author: joshgubler

README.md

@@ -27,7 +27,7 @@ Also Note: CodePipeline and CodeDeploy cannot be used together to deploy a Lambd
 For a Zip file lambda
 ```hcl
 module "lambda_api" {
-  source       = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.0"
+  source       = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.1"
   app_name     = "my-lambda-codedeploy-dev"
   zip_filename = "./src/lambda.zip"
   zip_handler  = "index.handler"
@@ -50,7 +50,7 @@ module "lambda_api" {
 For a docker image lambda:
 ```hcl
 module "lambda_api" {
-  source                        = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.0"
+  source                        = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.1"
   app_name                      = "my-docker-lambda"
   image_uri                     = "my-image-from-my-ecr:latest"
   hosted_zone                   = module.acs.route53_zone

examples/docker-lambda/docker.tf

@@ -9,7 +9,7 @@ module "acs" {
 
 module "lambda_api" {
   #  source                        = "../../"
-  source                        = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.0"
+  source                        = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.1"
   app_name                      = "my-docker-lambda"
   image_uri                     = "my-image-from-my-ecr:latest"
   hosted_zone                   = module.acs.route53_zone

examples/simple-lambda-in-vpc/example.tf

@@ -9,7 +9,7 @@ module "acs" {
 
 module "lambda_api" {
   # source                        = "../../"
-  source       = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.0"
+  source       = "github.com/byu-oit/terraform-aws-lambda-api?ref=v3.0.1"
   app_name     = "my-lambda-dev"
   zip_filename = "./src/lambda.zip"
   zip_handler  = "index.handler"

main.tf

@@ -30,7 +30,7 @@ locals {
 
 resource "aws_alb" "alb" {
   name                   = local.alb_name
-  desync_mitigation_mode = "strictest"
+  desync_mitigation_mode = "defensive"
   subnets                = var.public_subnet_ids
   security_groups        = [aws_security_group.alb-sg.id]
   tags                   = var.tags