Bump net.minecraftforge.gradle:ForgeGradle from 5.1.+ to 6.0.14

Bumps net.minecraftforge.gradle:ForgeGradle from 5.1.+ to 6.0.14.

---
updated-dependencies:
- dependency-name: net.minecraftforge.gradle:ForgeGradle
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle

@@ -14,7 +14,7 @@ buildscript {
         }
     }
     dependencies {
-        classpath group: 'net.minecraftforge.gradle', name: 'ForgeGradle', version: '5.1.+', changing: true
+        classpath group: 'net.minecraftforge.gradle', name: 'ForgeGradle', version: '6.0.+', changing: true
         classpath 'org.spongepowered:mixingradle:0.7.32'
     }
 }