update changelog for rc3 (cosmos#7843)

Stargate RC2 - Changelog updates & tag RC (cosmos#7785)

* update changelog with rc1 and rc2 entries

* add more rc2 changelog updates

Add CommunitySpendProposals in migration (cosmos#7607) (cosmos#7611)

* Add CommunitySpendProposals in migration

* Fix lint

* Avoid double registration

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Co-authored-by: Amaury Martiny <[email protected]>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Merge PR cosmos#7502: [Stargate] Merge & tag v0.40.0-rc0

Release v0.37.14

Release v0.39.1

v0.39.1 RC3

Release v0.39.1 RC2

Release v0.39.1-rc1

Release v0.39.0