CHANGELOG.md: Add entry for PR #646

Signed-off-by: Andrew Gunnerson <[email protected]>

CHANGELOG.md

@@ -17,6 +17,8 @@
 * Rebase icon off the latest material call and mic icons ([PR #635 @chenxiaolong])
 * Update Italian translations ([PR #637 @Strange-IPmart])
 * Fix regression from version 1.73 that caused BCR to crash when recording calls in direct boot mode ([Issue #643], [PR #645 @chenxiaolong])
+* Remove migration of the old global sample-rate option ([PR #646 @chenxiaolong])
+  * Folks upgrading from pre-1.62 versions should first upgrade to 1.74 first and then upgrade to this version.
 
 ### Version 1.74
 
@@ -1004,3 +1006,4 @@ Non-user-facing changes:
 [PR #637 @Strange-IPmart]: https://github.com/chenxiaolong/BCR/pull/637
 [PR #644 @chenxiaolong]: https://github.com/chenxiaolong/BCR/pull/644
 [PR #645 @chenxiaolong]: https://github.com/chenxiaolong/BCR/pull/645
+[PR #646 @chenxiaolong]: https://github.com/chenxiaolong/BCR/pull/646