Release version 3

* NEWS: Record release date.
maint: post-release administrivia.

* NEWS: Add header line for next release.
* .prev-version: Record previous version.
* ./local.mk (old_NEWS_hash): Auto-update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
Merge accidentally diverged branch 'pending'
mkrockspecs: lyaml 4 will be API compatible after all.

* src/mkrockspecs.in: Remove table hacks for previously expected
API incompatible lyaml 4.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>