[submodule] Update submodule sonic-gnmi to the latest HEAD automatically (#16014)

#### Why I did it
src/sonic-gnmi
```
* 58a7b20 - (HEAD -> master, origin/master, origin/HEAD) Add delete field to On change response when key is deleted (#139) (8 hours ago) [Zain Budhwani]
```
#### How I did it
#### How to verify it
#### Description for the changelog
This commit is contained in:
mssonicbld 2023-08-02 16:32:24 +08:00 committed by GitHub
parent 0474c296b1
commit 72ac5ccf1a
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23

@ -1 +1 @@
Subproject commit 2c8e4ab783d10b7433325653c1c90ad2b7f980b0
Subproject commit 58a7b20b760561dd4d1156e1e91d7addc434dc39