Add omitempty to ALBTargetGroupRequest.Body (#408)

If a lambda returns `Body: nil`, then the ALB returns a 502.

Co-authored-by: Bryan Moffatt <[email protected]>

Author: Hugo Osvaldo Barrera

events/alb.go

@@ -10,7 +10,7 @@ type ALBTargetGroupRequest struct {
 	MultiValueHeaders               map[string][]string          `json:"multiValueHeaders,omitempty"`
 	RequestContext                  ALBTargetGroupRequestContext `json:"requestContext"`
 	IsBase64Encoded                 bool                         `json:"isBase64Encoded"`
-	Body                            string                       `json:"body"`
+	Body                            string                       `json:"body,omitempty"`
 }
 
 // ALBTargetGroupRequestContext contains the information to identify the load balancer invoking the lambda

events/testdata/alb-lambda-target-request-headers-only.json

@@ -21,6 +21,5 @@
     "x-imforwards": "20",
     "x-myheader": "123"
   },
-  "body": "",
   "isBase64Encoded": false
-}
+}

events/testdata/alb-lambda-target-request-multivalue-headers.json

@@ -43,6 +43,6 @@
       "123"
     ]
   },
-  "body": "",
+  "body": "Some text",
   "isBase64Encoded": false
-}
+}