feat: remove username input

Logging into ghcr.io does not require that the username match the owner of the token.

docker/exec.go

@@ -13,11 +13,10 @@ import (
 	"syscall"
 )
 
-// Login executes a docker login to ghcr.io with the given username and
-// password.
-func Login(username, password string) error {
-	cmd := exec.Command("/usr/bin/docker", "login", "ghcr.io", "--username", username, "--password-stdin")
-	cmd.Stdin = strings.NewReader(password + "\n")
+// Login executes a docker login to ghcr.io with the given GitHub token.
+func Login(token string) error {
+	cmd := exec.Command("/usr/bin/docker", "login", "ghcr.io", "--username", "-", "--password-stdin")
+	cmd.Stdin = strings.NewReader(token + "\n")
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 

main.go

@@ -28,8 +28,6 @@ func mainCmd() error {
 	flag.StringVar(&image, "image", "", "ghcr.io image to run")
 	var tokenEnv string
 	flag.StringVar(&tokenEnv, "token-env", "", "env var to use for github token")
-	var username string
-	flag.StringVar(&username, "username", "", "username for github token")
 	flag.Parse()
 
 	if image == "" {
@@ -53,12 +51,8 @@ func mainCmd() error {
 		token = value
 	}
 
-	if username == "" {
-		username = os.Getenv("GITHUB_ACTOR")
-	}
-
 	fmt.Printf("::group::%s\n", "Docker login")
-	err := docker.Login(username, token)
+	err := docker.Login(token)
 	fmt.Println("::endgroup::")
 	if err != nil {
 		return err