Add EAP 6.4 to support matrix for JBDS 8.1

Last week, rhn-support-mus suggested we add EAP 6.4 to the support matrix:

Reading [1], I think this needs to be changed so that 8.0 and 8.1.0 list different
supported EAP versions?

Misha, can you update it based on the answers to the following?

• Does JBDS 8.0 support EAP 6.4.0? I don't believe EAP 6.4.0 was tested against JBDS 8.0.0
• EAP 6.4.0 should be listed under supported EAP versions for JBDS 8.1.0

Thanks
Mus

[1] https://access.redhat.com/articles/427493

I conducted testing of EAP 6.4 with JBDS 8.1 and found no issues, so I believe we can go ahead and add 6.4 to the document.

But in my opinion we don't have to distinguish JBDS 8.0 and 8.1 - there were no changes made to support 6.4, it works exactly the same way like 6.3, using the same EAP 6.1+ server adapter.

So I think we're fine just adding 6.4 to JBDS 8.0/8.1 in the document.