Do not require 'gpu-standard-v1' platform_id for any GPU-based config.

Support use another kind of GPU platforms.

builder/yandex/config.go

@@ -248,11 +248,6 @@ func (c *Config) Prepare(raws ...interface{}) ([]string, error) {
 		c.FolderID = os.Getenv("YC_FOLDER_ID")
 	}
 
-	if c.PlatformID != defaultGpuPlatformID && c.InstanceGpus != 0 {
-		errs = packer.MultiErrorAppend(
-			errs, fmt.Errorf("for instances with gpu platform_id must be specified as `%s`", defaultGpuPlatformID))
-	}
-
 	if c.Token == "" && c.ServiceAccountKeyFile == "" {
 		errs = packer.MultiErrorAppend(
 			errs, errors.New("a token or service account key file must be specified"))

builder/yandex/config_test.go

@@ -231,7 +231,7 @@ func TestGpuDefaultPlatformID(t *testing.T) {
 	var c Config
 	c.Prepare(raw)
 	if c.PlatformID != "gpu-standard-v1" {
-		t.Fatalf("expected 'gpu-standard-v1', but got '%s'", c.PlatformID)
+		t.Fatalf("expected 'gpu-standard-v1' as default platform_id for instance with GPU(s), but got '%s'", c.PlatformID)
 	}
 }