(torchx/docs) fix broken link in kubernetes docs due to github migration from pytorch to meta-pytorch

Summary:
TorchX migrated from https://github.com/pytorch/torchx to https://github.com/meta-pytorch/torchx hence the issue hyperlink in the kubernetes docstring was broken and failing the check-links doc test.

```
Warning, treated as error:
/home/runner/work/torchx/torchx/docs/source/schedulers/kubernetes.rst:8:broken link: #120 (404 Client Error: Not Found for url: #120)
make: *** [Makefile:29: linkcheck] Error 2
(schedulers/kubernetes: line    8) 
Error: Process completed with exit code 2.
```

Differential Revision: D83262154

Author: kiukchung

torchx/schedulers/kubernetes_scheduler.py

@@ -485,7 +485,7 @@ class KubernetesScheduler(
     For installation instructions see: https://github.com/volcano-sh/volcano
 
     This has been confirmed to work with Volcano v1.3.0 and Kubernetes versions
-    v1.18-1.21. See https://github.com/pytorch/torchx/issues/120 which is
+    v1.18-1.21. See https://github.com/meta-pytorch/torchx/issues/120 which is
     tracking Volcano support for Kubernetes v1.22.
 
     .. note::