[GoLang] Array Items anyOf do not properly map

Description

I have an object with a two-dimensional array, and the inner array items may be floator integer. If I attempt to generate the go client code it will create a nested map instead.

So instead of this:

Metrics map[string][][]map[string]interface{} `json:"metrics,omitempty"`

I was hoping for this:

Metrics map[string][][]interface{} `json:"metrics,omitempty"`

openapi-generator version

3.3.4

OpenAPI declaration file content or url

Command line used for generation

GO_POST_PROCESS_FILE="/usr/local/bin/gofmt -w" openapi-generator generate -i ../api/openapi.yaml -g go -o ../vendor/instana/openapi

Steps to reproduce

Create the client. (Bug is already apparent)
Invoke a service.
Note that JSON result cannot be mapped:
panic: json: cannot unmarshal number into Go struct field MetricItem.metrics of type map[string]interface {}

Related issues/PRs

Suggest a fix/enhancement

I would have to dive in, I assume that the problem lies in org.openapitools.codegen.languages. AbstractGoCodegen as it "overmatches" the object type. See typeMapping.put("object", "map[string]interface{}");

Start with org.openapitools.codegen.languages.AbstractGoCodegen and its typeMapping entry for object, using the supplied OpenAPI declaration and generation command to reproduce the issue. Confirm that the nested anyOf array generates Metrics as map[string][][]interface{} and that the resulting Go client can unmarshal numeric JSON results without the reported panic.