Update CHANGELOG.md

Author: oleibman

CHANGELOG.md

@@ -38,6 +38,8 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Problem rendering line chart with missing plot label. [PR #4074](https://github.com/PHPOffice/PhpSpreadsheet/pull/4074)
 - More RTL in Xlsx/Html Comments [Issue #4004](https://github.com/PHPOffice/PhpSpreadsheet/issues/4004) [PR #4065](https://github.com/PHPOffice/PhpSpreadsheet/pull/4065)
 - Empty String in sharedStrings. [Issue #4063](https://github.com/PHPOffice/PhpSpreadsheet/issues/4063) [PR #4064](https://github.com/PHPOffice/PhpSpreadsheet/pull/4064)
+- Changes to INDEX function. [Issue #64](https://github.com/PHPOffice/PhpSpreadsheet/issues/64) [PR #4088](https://github.com/PHPOffice/PhpSpreadsheet/pull/4088)
+- Ods Reader and Whitespace Text Nodes. [Issue #804](https://github.com/PHPOffice/PhpSpreadsheet/issues/804) [PR #4087](https://github.com/PHPOffice/PhpSpreadsheet/pull/4087)
 
 ## 2024-05-11 - 2.1.0