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

…#15634)

#### Why I did it
src/dhcpmon
```
* 824a144 - (HEAD -> master, origin/master, origin/HEAD) replace atoi with strtol (#6) (3 hours ago) [Mai Bui]
* 32c0c3f - Fix libswsscommon package installation for non-amd64 (#7) (6 hours ago) [Saikrishna Arcot]
```
#### How I did it
#### How to verify it
#### Description for the changelog