chore(entities): add missing reference to `GetTags()` in `interface_methods` of `EntityOutline`

[pranav-new-relic]

In #1146, a new method GetTags() was added to the interface EntityOutlineInterface.

This was supposed to be a change automated via Tutone, via the addition of GetTags() to the attribute interface_methods under EntityOutline similar to #595, however, the relevant commit which included changes to .tutone.yml went missing.

This PR is an attempt to add this capability back to Tutone, to prevent diffs generated because of the absence of GetTags() in interface_methods of EntityOutline.