Mark v1.20.0-rc2

[SpicyLemon]

Description

This PR marks v1.20.0-rc2 in the changelog and release changelog because v1.20.0-rc1 had the release changelog named the wrong thing, so it didn't actually create the release.

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Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md).
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/).
• Added relevant godoc comments.
• Added relevant changelog entries under .changelog/unreleased (see Adding Changes).
• Re-reviewed Files changed in the Github PR explorer.
• Review Codecov Report in the comment section below once CI passes.

[SpicyLemon]

Gonna need #2184 in this too, so putting it back into draft. It's in, so this is ready again.