Release 2.12.7

[cowtowncoder]

Time to release 2.12.7, the very last full release of 2.12 with these change(s):

https://github.com/FasterXML/jackson/wiki/Jackson-Release-2.12.7

Publish of the core components done, should be accessible via Maven Central.

... and then we can close 2.12 branch for good I hope :)

[pjfanning]

release done - should appear in maven central soon