Fixes update-link attribute

[khisakuni]

@jvandemo Fix for https://github.com/jvandemo/angular-update-meta/issues/28

• The attributes: rel, id will be used to target the link tag
• The supported attributes (href, charset, crossorigin, hreflang, integrity, media, methods, referrerpolicy, sizes, target, title, type) will be updated
• Updated docs to reflect this
• Added update-link example in the examples/all.html example file
• This is what was decided in the original PR https://github.com/jvandemo/angular-update-meta/pull/18, but I must've gotten confused before merging it in

Thanks @samsole4 for finding the fix

[jvandemo]

Merged and released as v2.0.1.

Thank you @khisakuni, much appreciated! 👍