fix: use correct ForgeGradle version and Minecraft version for 1.20.1

- Downgrade ForgeGradle from 6.0.24 to 5.2.5 (compatible with 1.20.1)
- Set minecraft.version to '1.20.1' in Forge build.gradle
- Remove exclusiveContent from Forge repo in settings.gradle

Author: Meeuyt

forge/build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id 'multiloader-loader'
-    id 'net.minecraftforge.gradle' version '6.0.24'
+    id 'net.minecraftforge.gradle' version '5.2.5'
 }
 
 tasks.javadoc {
@@ -12,7 +12,7 @@ tasks.named('processResources', ProcessResources) {
 }
 
 minecraft {
-    version = forge_version
+    version = '1.20.1'
     mappings channel: 'parchment', version: "${parchment_minecraft}-${parchment_version}"
     runs {
         client {