[submodule][master] Update submodule sonic-gnmi to the latest HEAD automatically

[mssonicbld]

Why I did it

src/sonic-gnmi

* 5357f93 - (HEAD -> master, origin/master, origin/HEAD) Fix yang validation (#244) (19 hours ago) [ganglv]
* 20aba13 - Improve GNMI incremental config and add unit test for BGP (#239) (2 days ago) [ganglv]
*   f0d0959 - Merge pull request #241 from liuh-80/dev/liuh/add_gnmi_cert_name (2 days ago) [Hua Liu]
|\  
| *   9b65bde - Merge branch 'master' into dev/liuh/add_gnmi_cert_name (2 days ago) [Hua Liu]
| |\  
| |/  
|/|   
* | 424212b - Add aaa ut (#222) (2 days ago) [ganglv]
 /  
* 90322b3 - Revert unecessary change (10 days ago) [liuh-80]
* b7abf5a - Fix comments (10 days ago) [liuh-80]
* f47be1c - Update server_test.go (11 days ago) [Hua Liu]
* 0ae9398 - Fix test case (12 days ago) [liuh-80]
* d305bca - Fix build issue (12 days ago) [liuh-80]
* 518b332 - Merge remote-tracking branch 'origin/master' into dev/liuh/add_gnmi_cert_name (12 days ago) [liuh-80]
* 0d30cfc - Fix yang issue (12 days ago) [liuh-80]
* f2882dd - Add cert role mapping (12 days ago) [liuh-80]
* 3ee207a - Update server_test.go (2 weeks ago) [Hua Liu]
* 0f211bf - Update server_test.go (2 weeks ago) [Hua Liu]
* 6b85507 - Improve coverage (2 weeks ago) [liuh-80]
* ec096c3 - Fix split method (2 weeks ago) [liuh-80]
* 43e7a43 - Improve code (2 weeks ago) [liuh-80]
* 7c4b830 - Improve code (3 weeks ago) [liuh-80]
* b998f4e - Improve code (3 weeks ago) [liuh-80]
* 795a52b - Improve code (3 weeks ago) [liuh-80]
* 08571e3 - Add cert authorization with common name support (3 weeks ago) [liuh-80]

How I did it

How to verify it

Description for the changelog

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).