cdc: command name in cli help is not correct

[pingyu]

Bug Report

1. Describe the bug

Command name in tikv-cdc cli --help is not correct. Should be tikv-cdc, but cdc instread.

❯ bin/tikv-cdc cli --help
Manage replication task and TiKV-CDC cluster

Usage:
  cdc cli [flags]
  cdc cli [command]

Available Commands:
  capture     Manage capture (capture is a CDC server instance)
  changefeed  Manage changefeed (changefeed is a replication task)
  processor   Manage processor (processor is a sub replication task running on a specified capture)
  tso         Manage tso

Flags:
      --ca string          CA certificate path for TLS connection
      --cert string        Certificate path for TLS connection
  -h, --help               help for cli
  -i, --interact           Run cdc cli with readline
      --key string         Private key path for TLS connection
      --log-level string   log level (etc: debug|info|warn|error) (default "warn")
      --pd string          PD address, use ',' to separate multiple PDs (default "http://127.0.0.1:2379")

Use "cdc cli [command] --help" for more information about a command.
❯ 

2. Minimal reproduce step (Required)

tikv-cdc cli --help

3. What did you see instead (Required)

Usage:
  tikv-cdc cli [flags]
  tikv-cdc cli [command]
...

4. What did you expect to see? (Required)

5. What is your migration tool and TiKV version? (Required)

• TiKV:
• TiKV CDC: master 9a226f07e90483b2b828de94c208d4d83cad8761
• TiKV BR:
• TiKV Online Bulk Load:

[pingyu]

cc @zeminzhou @haojinming