Update build.gradle to fix vulnerable sub-dependencies

Specifically: CVE-2022-42003, CVE-2021-46877, CVE-2022-42004, and CVE-2020-36518, all caused by com.fasterxml.jackson.core:jackson-databind version 2.13.0.

These vulnerabilities don't affect end users of the mod. Only developers were potentially affected. Then again, the attack vectors for these CVEs aren't super relevant when compiling Minecraft mods. So, do update your forks, but don't worry too much.

build.gradle

@@ -1,6 +1,6 @@
 buildscript {
 	dependencies {
-		classpath 'org.kohsuke:github-api:1.135'
+		classpath 'org.kohsuke:github-api:1.321'
 	}
 }