Update CHANGELOG.md

CHANGELOG.md

@@ -3,6 +3,10 @@ This is the changelog for the Fabric modpack [Fabulously Optimized](https://www.
 
 ## 1.21.3
 
+### 6.4.0-alpha.10-mr.1 (2024-12-01)
+
+A GitHub/Modrinth reupload to fix an error with the official installer. Identical to 6.4.0-alpha.10.
+
 ### 6.4.0-alpha.10 (2024-11-30)
 
 - Updated Fabric API, LambDynamicLights, MoreCulling, Polytone
@@ -88,6 +92,10 @@ Get your _bundle_ of mods in this update!
 
 ## 1.21.1
 
+### 6.2.3-mr.1 (2024-11-20)
+
+A GitHub-only version marking because 6.2.3 failed to upload to Modrinth due to my error. Identical to 6.2.3.
+
 ### 6.2.3 (2024-11-20)
 
 - Updated Entity Texture Features, Controlify, Fabric API, ImmediatelyFast, Lithium, No Chat Reports, Polytone