v3: Replace PackageName in config template with SrcPackageName

[LandonTClipp]

Inconfig.go:

	// data is the struct sent to the template parser
	data := struct {
		ConfigDir               string
		InterfaceDir            string
		InterfaceDirRelative    string
		InterfaceFile           string
		InterfaceName           string
		InterfaceNameCamel      string
		InterfaceNameLowerCamel string
		InterfaceNameSnake      string
		InterfaceNameLower      string
		Mock                    string
		MockName                string
		PackageName             string
		PackagePath             string
	}{
		ConfigDir:            filepath.Dir(c.Config),
		InterfaceDir:         filepath.Dir(iface.FileName),
		InterfaceDirRelative: interfaceDirRelative,
		InterfaceFile:        iface.FileName,
		InterfaceName:        iface.Name,
		// Deprecated: All custom case variables of InterfaceName will be removed in the next major version
		// Use the template functions instead
		InterfaceNameCamel:      strcase.ToCamel(iface.Name),
		InterfaceNameLowerCamel: strcase.ToLowerCamel(iface.Name),
		InterfaceNameSnake:      strcase.ToSnake(iface.Name),
		InterfaceNameLower:      strings.ToLower(iface.Name),
		Mock:                    mock,
		MockName:                c.MockName,
		PackageName:             iface.Pkg.Types.Name(),
		PackagePath:             iface.Pkg.Types.Path(),
	}

This is to disambiguate the source vs dest package naming.