kojiapi: make repo gpgkey optional

The kojiapi actually shouldn't require it as we need to build images from
unsigned packages.

Fixes #985

internal/kojiapi/api/api.gen.go

@@ -53,8 +53,8 @@ type Koji struct {
 
 // Repository defines model for Repository.
 type Repository struct {
-	Baseurl string `json:"baseurl"`
-	Gpgkey  string `json:"gpgkey"`
+	Baseurl string  `json:"baseurl"`
+	Gpgkey  *string `json:"gpgkey,omitempty"`
 }
 
 // Status defines model for Status.

internal/kojiapi/api/openapi.yml

@@ -176,7 +176,6 @@ components:
       type: object
       required:
         - baseurl
-        - gpgkey
       properties:
         baseurl:
           type: string