Bump LWJGL3 version to '3.2.1'

jme3-lwjgl3/build.gradle

@@ -2,7 +2,7 @@ if (!hasProperty('mainClass')) {
     ext.mainClass = ''
 }
 
-def lwjglVersion = '3.1.6'
+def lwjglVersion = '3.2.1'
 
 sourceCompatibility = '1.8'
 
@@ -31,4 +31,4 @@ dependencies {
     runtime "org.lwjgl:lwjgl-openal:${lwjglVersion}:natives-windows"
     runtime "org.lwjgl:lwjgl-openal:${lwjglVersion}:natives-linux"
     runtime "org.lwjgl:lwjgl-openal:${lwjglVersion}:natives-macos"
-}
+}