Update dependencies

vendor/tailscale.com/paths/migrate.go

@@ -0,0 +1,58 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package paths
+
+import (
+	"os"
+	"path/filepath"
+
+	"tailscale.com/types/logger"
+)
+
+// TryConfigFileMigration carefully copies the contents of oldFile to
+// newFile, returning the path which should be used to read the config.
+//   - if newFile already exists, don't modify it just return its path
+//   - if neither oldFile nor newFile exist, return newFile for a fresh
+//     default config to be written to.
+//   - if oldFile exists but copying to newFile fails, return oldFile so
+//     there will at least be some config to work with.
+func TryConfigFileMigration(logf logger.Logf, oldFile, newFile string) string {
+	_, err := os.Stat(newFile)
+	if err == nil {
+		// Common case for a system which has already been migrated.
+		return newFile
+	}
+	if !os.IsNotExist(err) {
+		logf("TryConfigFileMigration failed; new file: %v", err)
+		return newFile
+	}
+
+	contents, err := os.ReadFile(oldFile)
+	if err != nil {
+		// Common case for a new user.
+		return newFile
+	}
+
+	if err = MkStateDir(filepath.Dir(newFile)); err != nil {
+		logf("TryConfigFileMigration failed; MkStateDir: %v", err)
+		return oldFile
+	}
+
+	err = os.WriteFile(newFile, contents, 0600)
+	if err != nil {
+		removeErr := os.Remove(newFile)
+		if removeErr != nil {
+			logf("TryConfigFileMigration failed; write newFile no cleanup: %v, remove err: %v",
+				err, removeErr)
+			return oldFile
+		}
+		logf("TryConfigFileMigration failed; write newFile: %v", err)
+		return oldFile
+	}
+
+	logf("TryConfigFileMigration: successfully migrated: from %v to %v",
+		oldFile, newFile)
+
+	return newFile
+}