Improvement ideas for documentation

[rintisch]

I did not fully understand the documentation in two places:

Attributes in extension configuration

brevo/Readme.md

Lines 23 to 25 in d4c7b72

	- *Attribute for first name*: Name of attribute used for the first name
	- *Attribute for last name*: Name of attribute used for the last name
	- *Attribute for tracking information*: Name of attribute used for the tracking information

From the documentation I could not understand what this does. The default values are FIRSTNAME, LASTNAME and TRACKING. As I can see from the code are those values used as keys which are passed to Brevo, see

brevo/Classes/Finishers/BrevoFinisher.php

Line 141 in d4c7b72

protected function getAttributes(): object

and

brevo/Classes/Finishers/BrevoFinisher.php

Line 59 in d4c7b72

protected function addEntryToBrevo(): bool

So it might be worth to add a comment what they are used for and that these values can stay as they are?

11 contacts are needed

I could on https://help.brevo.com/hc/en-us/articles/360016175440 not find the fact that I need at least 11 contacts as claimed in

brevo/Readme.md

Lines 49 to 51 in d4c7b72

	In short you need
	1) At least **11** contacts. You can create any contact

To me this seems outdated?

I could make a PR but wanted to ask first whether I missed something.

Thanks for this extension!