5.6 Release Notes

[djbrooke]

It's that time again, another release!

[poikilotherm]

Would be nice to wait a bit:

• Sec38 div issues #8000 is nearly there. Some tests failing still due to not being atomic.
• 7700 payara 5.2021.4 #7701 has been merged for this release. Yesterday, Payara 5.2021.5 has been released. Should we go for that version then, given that there is a security fix in the EL parser? (Happy to create another small PR like 7700 payara 5.2021.4 #7701 done chore(payara): update everything to Payara 5.2021.5 #8030 #8031)