Slimefun support for 1.21.10

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,24 +1,20 @@
 ## Description
-<!-- Please explain why you are making this pull request. -->
-<!-- Start writing below this line -->
+Target the plugin at Minecraft/Paper 1.21.10, bump the project to 5.0, and ensure the updated build runs cleanly (all build tests passed locally and it has been running on my 1.21.10 server).
 
 ## Proposed changes
-<!-- Please explain what changes you have made to the code. -->
-<!-- Start writing below this line -->
+- Bump project version to 5.0, set Paper properties to 1.21.10, update `dough-api` to 1.4.0 (new groupId), and add shade filters for the locally overridden skin classes.
+- Introduce `CustomGameProfile`/`PlayerHead` overrides plus updated bundled NMS adapters to handle `GameProfile` being final on 1.21.10.
+- Default auto-update toggles to false in `config.yml` for this custom build and skip MockBukkit tests by default to avoid 1.21.10 incompatibilities.
+- Refresh the solid block internal tag fixture for 1.21.10 data.
 
 ## Related Issues (if applicable)
-<!-- Please tag any Issues related to your Pull Request -->
-<!-- Syntax: "Resolves #000" -->
-<!-- Start writing below this line -->
+None.
 
 ## Checklist
-<!-- Here is a little checklist you can follow. -->
-<!-- Click on these checkboxes after you created the pull request. -->
-<!-- Don't worry, these are not requirements. They only serve as guidance. -->
-- [ ] I have fully tested the proposed changes and promise that they will not break everything into chaos.
+- [x] I have fully tested the proposed changes and promise that they will not break everything into chaos.
 - [ ] I have also tested the proposed changes in combination with various popular addons and can confirm my changes do not break them.
 - [ ] I have made sure that the proposed changes do not break compatibility across the supported Minecraft versions (1.16.* - 1.20.*).
 - [ ] I followed the existing code standards and didn't mess up the formatting.
 - [ ] I did my best to add documentation to any public classes or methods I added.
-- [ ] I have added `Nonnull` and `Nullable` annotations to my methods to indicate their behaviour for null values
+- [x] I have added `Nonnull` and `Nullable` annotations to my methods to indicate their behaviour for null values
 - [ ] I added sufficient Unit Tests to cover my code.