[sairedis]: Update submodule

This brings in the following changes:

```
21f3d7c Add SAI_OBJECT_TYPE_TUNNEL object to break-before-make list (#1075)
8ac3aa7 [sairedis] Fix reopen recoding file (#1087)
0bbbb02 Transfer organization from Azure to sonic-net (#1096)
3406c57 [sairedis] Perform log rotate on request (#1083)
```

Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>