Build: Add github release command to build/cmd (#56349)

* Add github release command to build/cmd

* Use go-github library and implement dry-run

* Make tag optional and default to metadata

* Fix minor bug with tag default

* Make some refactors to ease testing

* Add tests for publish github command

* Refactor publish github tests

* Refactor test helper function name

* Isolate local test

pkg/build/cmd/main.go

@@ -232,6 +232,32 @@ func main() {
 						},
 					},
 				},
+				{
+					Name:   "github",
+					Usage:  "Publish packages to GitHub releases",
+					Action: PublishGitHub,
+					Flags: []cli.Flag{
+						&dryRunFlag,
+						&cli.StringFlag{
+							Name:     "path",
+							Required: true,
+							Usage:    "Path to the asset to be published",
+						},
+						&cli.StringFlag{
+							Name:     "repo",
+							Required: true,
+							Usage:    "GitHub repository",
+						},
+						&cli.StringFlag{
+							Name:  "tag",
+							Usage: "Release tag (default from metadata)ß",
+						},
+						&cli.BoolFlag{
+							Name:  "create",
+							Usage: "Create release if it doesn't exist",
+						},
+					},
+				},
 			},
 		},
 	}