grim/pidgin

Bump the version and update ChangeLog for the 2.14.7 release
release-2.x.y v2.14.7
2021-09-16, Gary Kramlich
f7894672b4e3
Bump the version and update ChangeLog for the 2.14.7 release

Testing Done:
Ran `make distcheck`

Reviewed at https://reviews.imfreedom.org/r/925/
installed_m4=purple.m4
EXTRA_DIST=$(installed_m4)
m4datadir=$(datadir)/aclocal
m4data_DATA=$(installed_m4)