Add ability to customize `$constructorName` in testify template

[satazor]

Currently, $constructorName cannot be customized on the testify template. Would you be open to add the ability to customize it via template-data.constructor-name?

Thanks in advance.

[satazor]

I've managed to do this via a custom template which was a copy of testify:

{{- $constructorName := "" }}
{{- if (index .TemplateData "constructor-name") }}
{{- $constructorName = index .TemplateData "constructor-name" }}
{{- else }}
{{ $new := "New" }}
{{ if firstIsLower .StructName }}
{{ $new = "new" }}
{{- end }}
{{- $constructorName = printf "%s%s" $new (.StructName | firstUpper) }}
{{- end }}

But it would be awesome if we could have this built-in

[LandonTClipp]

I think I'm open to this. One thing is that we probably want constructor-name to be a templated parameter so that it can be set generally at the config top-level. As far as I remember, template-data parameters aren't templated at all because mockery doesn't necessarily know what parameters will exist (unless we do something really funky like parsing the JSON schema to infer it ☹️ ). This could be done, but my overall point is that to make this feature-complete would require more work than just adding this parameter as you've done.