Thermoo 7 for Minecraft 1.21.6

This update brings Thermoo to 1.21.6. Per the LTS policy, this release also represents the end of support for 1.21.5. This version will likely also work on 1.21.7, when that version releases.

There is one notable breaking change in this update: The status bar overlay events have been refactored to reduce complexity, prevent errors, and be more extensible for future updates (if needed). See #82 for details.

To summarize, the main changes look something like this:

-StatusBarOverlayRenderEvents.AFTER_HEALTH_BAR.register(
-  (DrawContext ctx, PlayerEntity player, Vector2i[] positions, int displayHealth, int maxDisplayHealth)-> {
-    // rendering code
- });

+StatusBarOverlayRenderEvents.AFTER_HEALTH_BAR.register(
+  (DrawContext ctx, PlayerEntity player, HeartBarContext heartBarContext) -> {
+    SequencedCollection<Vector2i> positions = heartBarContext.positions();
+    int displayHealth = heartBarContext.currentDisplayHalfHearts();
+    int maxDisplayHealth = heartBarContext.maxDisplayHalfHearts();
+
+    // rendering code
+ });