Allow using key-value data

cmd/docker-buildx/config.go

@@ -159,11 +159,11 @@ func settingsFlags(settings *plugin.Settings) []cli.Flag {
 			Value:       true,
 			Destination: &settings.Build.LabelsAuto,
 		},
-		&cli.StringSliceFlag{
+		&cli.StringFlag{
 			Name:        "args",
 			EnvVars:     []string{"PLUGIN_BUILD_ARGS"},
-			Usage:       "sets custom build arguments for the build",
-			Destination: &settings.Build.Args,
+			Usage:       "sets custom build arguments for the build. Must be a JSON string",
+			Destination: &settings.Build.ArgsRaw,
 		},
 		&cli.StringSliceFlag{
 			Name:        "args-from-env",

cmd/docker-buildx/main.go

@@ -19,7 +19,7 @@ func main() {
 	if _, err := os.Stat("/run/drone/env"); err == nil {
 		godotenv.Overload("/run/drone/env")
 	}
-	
+
 	if envFile, set := os.LookupEnv("PLUGIN_ENV_FILE"); set {
 		godotenv.Overload(envFile)
 	}