fix: don't use filename from URL when downloading manifest

Manifest URL might be anything, including any GET parameters which might
get into filename which might lead to 'filename too long' error. As each
URL is downloaded to a separate temporary directory, there's no reason
to use filename based on the URL.

Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>

internal/app/machined/pkg/controllers/k8s/extra_manifest.go

@@ -141,8 +141,6 @@ func (ctrl *ExtraManifestController) download(ctx context.Context, r controller.
 
 	defer os.RemoveAll(tmpDir) //nolint: errcheck
 
-	fileName := filepath.Base(manifest.URL)
-
 	// I wish we never used go-getter package, as it doesn't allow downloading into memory.
 	// But there's not much we can do about it right now, as it supports lots of magic
 	// users might rely upon now.
@@ -166,7 +164,7 @@ func (ctrl *ExtraManifestController) download(ctx context.Context, r controller.
 	client := &getter.Client{
 		Ctx:     ctx,
 		Src:     manifest.URL,
-		Dst:     filepath.Join(tmpDir, fileName),
+		Dst:     filepath.Join(tmpDir, "manifest.yaml"),
 		Pwd:     tmpDir,
 		Mode:    getter.ClientModeFile,
 		Options: []getter.ClientOption{},