fix: allow multiple filters in event source mapping filter criteria

[moritzzimmer]

what

AWS Lambda service supports up to five different filters for a single event source. This module allowed only one so far which will be fixed with this PR.

The hcl changed from object to set of objects:

filter_criteria = [
  {
    pattern = jsonencode({
      data : {
        type : ["value"]
      }
    })
  }
]

Clients omitting this config change will be able to terraform apply but will loose the filter patterns:

# module.test.aws_lambda_event_source_mapping.event_source["delivery"] will be updated in-place
  ~ resource "aws_lambda_event_source_mapping" "event_source" {
        id                                 = "some-id"
        # (20 unchanged attributes hidden)


      ~ filter_criteria {
          + filter {}
          - filter {
              - pattern = jsonencode(
                    {
                      - data = {
                          - type = [
                              - "value",
                            ]
                        }
                    }
                ) -> null
            }
        }
        # (1 unchanged block hidden)
    }