update the Jolt-Physics source and assets to 153fd6f (sg260518)

Author: stephengold

build.gradle

@@ -19,7 +19,7 @@ plugins {
 
 ext {
     joltFork = 'stephengold'
-    joltTag = 'sg260506'
+    joltTag = 'sg260518'
     downloadedHairStraightZip = "downloads/wStraightHair.zip"
     downloadedJoltZip = "downloads/JoltPhysics-${joltTag}.zip"
     downloadedVhacdZip = 'downloads/v-hacd-4.1.0.zip'