Update README.adoc

[shavidissa]

Update the doc because the freemium account is not available anymore.

[shavidissa]

CC: @snicoll @jonatan-ivanov

[jonatan-ivanov]

Thank you for the heads up!
I'm wondering if https://github.com/wavefrontHQ/wavefront-spring-boot should be retired with it.

[Buzzardo]

LGTM

[shavidissa]

Thank you for the heads up! I'm wondering if https://github.com/wavefrontHQ/wavefront-spring-boot should be retired with it.

Good point. Will ask our PM Kushagra about it. I missed removing the freemium part from that repo. Will work on that too.

[shakuzen]

I missed removing the freemium part from that repo. Will work on that too.

I think the freemium part is the only code remaining in the repo for use with Spring Boot 3 anyway. If freemium accounts are no longer available, that code repository can probably be archived entirely.