Tell Proguard to keep all members of caffeine cache in JavaBuilder proguarded jar.

PiperOrigin-RevId: 259450655
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
index b18430f..2c73ff5 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
@@ -273,6 +273,7 @@
             @Override
             protected Class<?> findClass(String name) throws ClassNotFoundException {
               if (name.startsWith("com.google.errorprone.")
+                  || name.startsWith("com.github.benmanes.caffeine.cache.")
                   || name.startsWith("com.google.common.collect.")
                   || name.startsWith("com.google.common.base.")
                   || name.startsWith("org.checkerframework.dataflow.")