env var GITEA_PUSHER_EMAIL (#4516)

* env var GITEA_PUSHER_EMAIL

* set pusher email only if email address is not private

models/update.go

 	EnvRepoUsername = "GITEA_REPO_USER_NAME"
 	EnvRepoIsWiki   = "GITEA_REPO_IS_WIKI"
 	EnvPusherName   = "GITEA_PUSHER_NAME"
+	EnvPusherEmail  = "GITEA_PUSHER_EMAIL"
 	EnvPusherID     = "GITEA_PUSHER_ID"
 )
 

routers/repo/http.go

 			models.EnvPusherID + fmt.Sprintf("=%d", authUser.ID),
 			models.ProtectedBranchRepoID + fmt.Sprintf("=%d", repo.ID),
 		}
+
+		if !authUser.KeepEmailPrivate {
+			environ = append(environ, models.EnvPusherEmail+"="+authUser.Email)
+		}
+
 		if isWiki {
 			environ = append(environ, models.EnvRepoIsWiki+"=true")
 		} else {