docs: remove shim_no_newns in ops.md
this ops is removed in commit
remove from doc avoid misleading users.
@@ -216,9 +216,6 @@ The linux runtime allows a few options to be set to configure the shim and the r
no_shim = false
# display shim logs in the containerd daemon's log output
shim_debug = true
- # do not put the shim in its own mount namespace
- # (this only need to be set on kernel < 3.18)
- shim_no_newns = true
```
### Bolt Metadata Plugin
