[submodule] Update submodule dhcpmon to the latest HEAD automatically (…

…sonic-net#16227)

#### Why I did it
src/dhcpmon
```
* a3c5381 - (HEAD -> master, origin/master, origin/HEAD) Merge pull request #11 from jcaiMR/dev/jcai_fix_err_log (12 hours ago) [StormLiangMS]
* ab78a31 - Merge branch 'master' into dev/jcai_fix_err_log (4 days ago) [jcaiMR]
* 5314b72 - remove unnessary log message in case too many log output (5 days ago) [jcaiMR]
* 01f4fa7 - fix build issue (5 days ago) [jcaiMR]
* c2fbb34 - fix format issue (5 days ago) [jcaiMR]
* 79b6720 - fix a notification message format issue (6 days ago) [jcaiMR]
```
#### How I did it
#### How to verify it
#### Description for the changelog