update CHANGELOG (#2621)

Co-authored-by: Pascal Seitz <pascal.seitz@datadoghq.com>

Author: PSeitz

CHANGELOG.md

@@ -1,6 +1,6 @@
-Tantivy 0.23 - Unreleased
+Tantivy 0.24
 ================================
-Tantivy 0.23 will be backwards compatible with indices created with v0.22 and v0.21. The new minimum rust version will be 1.75.
+Tantivy 0.24 will be backwards compatible with indices created with v0.22 and v0.21. The new minimum rust version will be 1.75. Tantivy 0.23 will be skipped.
 
 #### Bugfixes
 - fix potential endless loop in merge [#2457](https://github.com/quickwit-oss/tantivy/pull/2457)(@PSeitz)