Merge #5921: chore: set IS_RELEASE to true

0737d7e chore: set IS_RELEASE to true (pasta)

Pull request description:

  ## Issue being fixed or feature implemented
  Release v20.1.0 final

  ## 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)_

Top commit has no ACKs.

Tree-SHA512: a83e8fea96d3d9106984be7f1a235116d99a98dc7a2fb436c58690731dbb2221ba691081ff2afd7d99f444baa02ff147e0d5a467c3213e33cf0f173db2b96e53

Author: PastaPastaPasta

configure.ac

@@ -3,7 +3,7 @@ dnl Don't forget to push a corresponding tag when updating any of _CLIENT_VERSIO
 define(_CLIENT_VERSION_MAJOR, 20)
 define(_CLIENT_VERSION_MINOR, 1)
 define(_CLIENT_VERSION_BUILD, 0)
-define(_CLIENT_VERSION_IS_RELEASE, false)
+define(_CLIENT_VERSION_IS_RELEASE, true)
 define(_COPYRIGHT_YEAR, 2024)
 define(_COPYRIGHT_HOLDERS,[The %s developers])
 define(_COPYRIGHT_HOLDERS_SUBSTITUTION,[[Dash Core]])