func (s *PackagesService) DeleteProjectPackage(pid interface{}, pkg int, options ...RequestOptionFunc) (*Response, error) {
	project, err := parseID(pid)
	if err != nil {
		return nil, err
	}
	u := fmt.Sprintf("projects/%s/packages/%d", pathEscape(project), pkg)
	req, err := s.client.NewRequest(http.MethodDelete, u, nil, options)
	if err != nil {
		return nil, err
	}
	return s.client.Do(req, nil)
}
DeleteProjectPackage deletes a package in a project.

GitLab API docs:
https://docs.gitlab.com/ee/api/packages.html#delete-a-project-package
package gitlab
import (
	"fmt"
	"net/http"
	"time"
)
type PackagesService struct {
	client *Client
}
type Package struct {
	ID          int           `json:"id"`
	Name        string        `json:"name"`
	Version     string        `json:"version"`
	PackageType string        `json:"package_type"`
	Links       *PackageLinks `json:"_links"`
	CreatedAt   *time.Time    `json:"created_at"`
}
func (s Package) String() string {
	return Stringify(s)
}
type PackageLinks struct {
	WebPath       string `json:"web_path"`
	DeleteAPIPath string `json:"delete_api_path"`
}
func (s PackageLinks) String() string {
	return Stringify(s)
}
type PackageFile struct {
	ID        int         `json:"id"`
	PackageID int         `json:"package_id"`
	CreatedAt *time.Time  `json:"created_at"`
	FileName  string      `json:"file_name"`
	Size      int         `json:"size"`
	FileMD5   string      `json:"file_md5"`
	FileSHA1  string      `json:"file_sha1"`
	Pipeline  *[]Pipeline `json:"pipelines"`
}
func (s PackageFile) String() string {
	return Stringify(s)
}
type ListProjectPackagesOptions struct {
	ListOptions
	OrderBy            *string `url:"order_by,omitempty" json:"order_by,omitempty"`
	Sort               *string `url:"sort,omitempty" json:"sort,omitempty"`
	PackageType        *string `url:"package_type,omitempty" json:"package_type,omitempty"`
	PackageName        *string `url:"package_name,omitempty" json:"package_name,omitempty"`
	IncludeVersionless *bool   `url:"include_versionless,omitempty" json:"include_versionless,omitempty"`
}
func (s *PackagesService) ListProjectPackages(pid interface{}, opt *ListProjectPackagesOptions, options ...RequestOptionFunc) ([]*Package, *Response, error) {
	project, err := parseID(pid)
	if err != nil {
		return nil, nil, err
	}
	u := fmt.Sprintf("projects/%s/packages", pathEscape(project))
	req, err := s.client.NewRequest(http.MethodGet, u, opt, options)
	if err != nil {
		return nil, nil, err
	}
	var ps []*Package
	resp, err := s.client.Do(req, &ps)
	if err != nil {
		return nil, resp, err
	}
	return ps, resp, err
}
type ListPackageFilesOptions ListOptions
func (s *PackagesService) ListPackageFiles(pid interface{}, pkg int, opt *ListPackageFilesOptions, options ...RequestOptionFunc) ([]*PackageFile, *Response, error) {
	project, err := parseID(pid)
	if err != nil {
		return nil, nil, err
	}
	u := fmt.Sprintf(
		"projects/%s/packages/%d/package_files",
		pathEscape(project),
		pkg,
	)
	req, err := s.client.NewRequest(http.MethodGet, u, opt, options)
	if err != nil {
		return nil, nil, err
	}
	var pfs []*PackageFile
	resp, err := s.client.Do(req, &pfs)
	if err != nil {
		return nil, resp, err
	}
	return pfs, resp, err
}