Please add a brief but descriptive title

## What do you need help with?
What do I need exactly to build the latest 1.21.5 myself?

Tried downloading the latest source code and running gradlew build but I get this error. I tried the exact same thing with 1.21.1 and it worked fine. I'd like to build it myself because I want to change how the farming command works so downloading a existing jar is not a possibility.
Here the error:
baritone-1.14.0\src\api\java\baritone\api\utils\BlockOptionalMeta.java:39: error: package net.minecraft.server.packs.resources does not exist
import net.minecraft.server.packs.resources.CloseableResourceManager;
^
baritone-1.14.0\src\api\java\baritone\api\BaritoneAPI.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
100 errors
only showing the first 100 errors, of 886 total; use -Xmaxerrs if you would like to see more

> Task :compileApiJava FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileApiJava'.
> Compilation failed; see the compiler error output for details.

* Try:
> Run with --info option to get more log output.
> Run with --scan to get full insights.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.7/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.

BUILD FAILED in 5s
3 actionable tasks: 3 executed

## Final checklist
- [] Know how exactly to run build in latest.