Enhancement to Add Support for Discussions Webhook Event (google#2221)

This commit has changes to enable support to receive Discussions Webhook Events, to fix google#2221.
Changes include:
- Addition of event type for this type of event
- Changes for identification and mapping of DiscussionEvent
- Addition / Modification of relevent tests
- Addition of files created by go generate

github/event.go

@@ -50,6 +50,8 @@ func (e *Event) ParsePayload() (payload interface{}, err error) {
 		payload = &DeploymentEvent{}
 	case "DeploymentStatusEvent":
 		payload = &DeploymentStatusEvent{}
+	case "DiscussionEvent":
+		payload = &DiscussionEvent{}
 	case "ForkEvent":
 		payload = &ForkEvent{}
 	case "GitHubAppAuthorizationEvent":

github/event_types.go

@@ -180,6 +180,59 @@ type DeploymentStatusEvent struct {
 	Installation *Installation `json:"installation,omitempty"`
 }
 
+// DiscussionEvent represents a webhook event for a discussion.
+// The Webhook event name is "discussion".
+//
+// GitHub API docs: https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads#discussion
+type DiscussionEvent struct {
+	// Action is the action that was performed. Possible values are:
+	// created, edited, deleted, pinned, unpinned, locked, unlocked,
+	// transferred, category_changed, answered, or unanswered.
+	Action       *string       `json:"action,omitempty"`
+	Discussion   *Discussion   `json:"discussion,omitempty"`
+	Repo         *Repository   `json:"repository,omitempty"`
+	Org          *Organization `json:"organization,omitempty"`
+	Sender       *User         `json:"sender,omitempty"`
+	Installation *Installation `json:"installation,omitempty"`
+}
+
+// Discussion represents a discussion in a GitHub DiscussionEvent.
+type Discussion struct {
+	RepositoryURL      *string             `json:"repository_url,omitempty"`
+	DiscussionCategory *DiscussionCategory `json:"category,omitempty"`
+	AnswerHtmlUrl      *string             `json:"answer_html_url,omitempty"`
+	AnswerChosenAt     *string             `json:"answer_chosen_at,omitempty"`
+	AnswerChosenBy     *string             `json:"answer_chosen_by,omitempty"`
+	HTMLURL            *string             `json:"html_url,omitempty"`
+	ID                 *int64              `json:"id,omitempty"`
+	NodeID             *string             `json:"node_id,omitempty"`
+	Number             *int64              `json:"number,omitempty"`
+	Title              *string             `json:"title,omitempty"`
+	User               *User               `json:"user,omitempty"`
+	State              *string             `json:"state,omitempty"`
+	Locked             *bool               `json:"locked,omitempty"`
+	Comments           *int                `json:"comments,omitempty"`
+	CreatedAt          *Timestamp          `json:"created_at,omitempty"`
+	UpdatedAt          *Timestamp          `json:"updated_at,omitempty"`
+	AuthorAssociation  *string             `json:"author_association,omitempty"`
+	ActiveLockReason   *string             `json:"active_lock_reason,omitempty"`
+	Body               *string             `json:"body,omitempty"`
+}
+
+// DiscussionCategory represents a discussion category in a GitHub DiscussionEvent.
+type DiscussionCategory struct {
+	ID           *int64     `json:"id,omitempty"`
+	NodeID       *string    `json:"node_id,omitempty"`
+	RepositoryID *int64     `json:"repository_id,omitempty"`
+	Emoji        *string    `json:"emoji,omitempty"`
+	Name         *string    `json:"name,omitempty"`
+	Description  *string    `json:"description,omitempty"`
+	CreatedAt    *Timestamp `json:"created_at,omitempty"`
+	UpdatedAt    *Timestamp `json:"updated_at,omitempty"`
+	Slug         *string    `json:"slug,omitempty"`
+	IsAnswerable *bool      `json:"is_answerable,omitempty"`
+}
+
 // ForkEvent is triggered when a user forks a repository.
 // The Webhook event name is "fork".
 //