Breaking: Revert "Breaking: Fix plugin addition"

[Code-Hex]

Reverts #1717

• Some plugins that worked in versions prior to v0.15, which generated code based on a previously generated model, no longer work above v0.15.

  • gqlgen/api/generate.go

    Lines 21 to 32 in 8b25c9e

    	plugins := []plugin.Plugin{}
    	if cfg.Model.IsDefined() {
    	plugins = append(plugins, modelgen.New())
    	}
    	plugins = append(plugins, resolvergen.New())
    	if cfg.Federation.IsDefined() {
    	plugins = append([]plugin.Plugin{federation.New()}, plugins...)
    	}
    	for _, o := range option {
    	o(cfg, &plugins)
    	}

• I think we shouldn't implicit breaking changes should be made
• If we want to achieve the behavior he claims, we should create a new API.
  • e.g. func PrependPlugin

[coveralls]

Coverage decreased (-0.04%) to 74.923% when pulling a0fada2 on Code-Hex:revert-1717-add-plugin-fix into fcee4c4 on 99designs:master.