Bump github.com/spf13/cobra from 1.2.0 to 1.2.1

Bumps [github.com/spf13/cobra](https://github.com/spf13/cobra) from 1.2.0 to 1.2.1.
- [Release notes](https://github.com/spf13/cobra/releases)
- [Changelog](https://github.com/spf13/cobra/blob/master/CHANGELOG.md)
- [Commits](https://github.com/spf13/cobra/compare/v1.2.0...v1.2.1)

---
updated-dependencies:
- dependency-name: github.com/spf13/cobra
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/spf13/cobra/bash_completions.go

@@ -512,7 +512,9 @@ func writeLocalNonPersistentFlag(buf io.StringWriter, flag *pflag.Flag) {
 
 // Setup annotations for go completions for registered flags
 func prepareCustomAnnotationsForFlags(cmd *Command) {
-	for flag := range cmd.Root().flagCompletionFunctions {
+	flagCompletionMutex.RLock()
+	defer flagCompletionMutex.RUnlock()
+	for flag := range flagCompletionFunctions {
 		// Make sure the completion script calls the __*_go_custom_completion function for
 		// every registered flag.  We need to do this here (and not when the flag was registered
 		// for completion) so that we can know the root command name for the prefix