Update docs/upgrade/v1-5-x-to-v1-6-0.md

Co-authored-by: Daria Vladykina <[email protected]>
Signed-off-by: PoAn Yang <[email protected]>

Author: FrankYang0529

docs/upgrade/v1-5-x-to-v1-6-0.md

@@ -235,7 +235,7 @@ stages:
 ```
 The typical expectation is that an additional VLAN sub-interface is created on the `mgmt` interface (`mgmt-br.2113`) and assigned an IPv4 address. In addition, this sub-interface and the primary interface (`mgmt-br.2021`) are both expected to be used for L3 connectivity after the cluster is upgraded to v1.6.x.
 
-In actuality after upgrade to v1.6.0, however, the VLAN sub-interface is created but the secondary VLAN (VLAN ID: `2113`) is removed from the `mgmt-br` bridge and the `mgmt-bo` interface. After a reboot, only the primary VLAN ID is assigned to the `mgmt-br` bridge and the `mgmt-bo` interface (using the `/oem/90_custom.yaml` file).
+In actuality, after the upgrade to v1.6.0, however, the VLAN sub-interface is created but the secondary VLAN (VLAN ID: `2113`) is removed from the `mgmt-br` bridge and the `mgmt-bo` interface. After a reboot, only the primary VLAN ID is assigned to the `mgmt-br` bridge and the `mgmt-bo` interface (using the `/oem/90_custom.yaml` file).
 To mitigate the effects of this change, you must perform the workaround described in the previous section. This involves identifying secondary VLAN interfaces and then adding the necessary ones to the `mgmt-br` bridge and the `mgmt-bo` interface.
 
 ### 6. Running VMs show "Restart action is required for the virtual machine configuration change to take effect"