Update RFG to 1.3.21

Author: serenibyss

build.gradle

@@ -23,7 +23,7 @@ plugins {
     id 'eclipse'
     id 'maven-publish'
     id 'org.jetbrains.gradle.plugin.idea-ext' version '1.1.7'
-    id 'com.gtnewhorizons.retrofuturagradle' version '1.3.20'
+    id 'com.gtnewhorizons.retrofuturagradle' version '1.3.21'
     id 'net.darkhax.curseforgegradle' version '1.0.14' apply false
     id 'com.modrinth.minotaur' version '2.8.0' apply false
     id 'com.diffplug.spotless' version '6.13.0' apply false
@@ -961,7 +961,7 @@ def getChangelog() {
 
 // Buildscript updating
 
-def buildscriptGradleVersion = '8.1.1'
+def buildscriptGradleVersion = '8.2.1'
 
 tasks.named('wrapper', Wrapper).configure {
     gradleVersion = buildscriptGradleVersion