chore: set release version to true; set rc to 0 (#5695)

## Issue being fixed or feature implemented
Bump release to true; rc to 0

This should be the final PR merged to v20.x branch

## What was done?


## How Has This Been Tested?


## Breaking Changes


## Checklist:
_Go over all the following points, and put an `x` in all the boxes that
apply._
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [ ] I have made corresponding changes to the documentation
- [x] I have assigned this pull request to a milestone _(for repository
code-owners and collaborators only)_

configure.ac

@@ -2,8 +2,8 @@ AC_PREREQ([2.69])
 define(_CLIENT_VERSION_MAJOR, 20)
 define(_CLIENT_VERSION_MINOR, 0)
 define(_CLIENT_VERSION_BUILD, 0)
-define(_CLIENT_VERSION_RC, 2)
-define(_CLIENT_VERSION_IS_RELEASE, false)
+define(_CLIENT_VERSION_RC, 0)
+define(_CLIENT_VERSION_IS_RELEASE, true)
 define(_COPYRIGHT_YEAR, 2023)
 define(_COPYRIGHT_HOLDERS,[The %s developers])
 define(_COPYRIGHT_HOLDERS_SUBSTITUTION,[[Dash Core]])