Tags can't be removed in cloned plugins using decK

[harshadixit12]

To recreate -
step 1:

_format_version: "3.0"
cloned_plugins:
- name: new-acl
  ref: acl
  priority: 1000
  tags:
  - tag1
  - tag2

Run deck gateway sync, and then
step 2:

_format_version: "3.0"
cloned_plugins:
- name: new-acl
  ref: acl
  priority: 1000

Now, running deck gateway sync continues to show drift.