Support collect ZGC memory pool metrics (#86)

diff --git a/language-agent/JVMMetric.proto b/language-agent/JVMMetric.proto
index a4808f7..e0d55ed 100644
--- a/language-agent/JVMMetric.proto
+++ b/language-agent/JVMMetric.proto
@@ -73,6 +73,11 @@
     SURVIVOR_USAGE = 3;
     PERMGEN_USAGE = 4;
     METASPACE_USAGE = 5;
+    ZHEAP_USAGE = 6;
+    COMPRESSED_CLASS_SPACE_USAGE = 7;
+    CODEHEAP_NON_NMETHODS_USAGE = 8;
+    CODEHEAP_PROFILED_NMETHODS_USAGE = 9;
+    CODEHEAP_NON_PROFILED_NMETHODS_USAGE = 10;
 }
 
 message GC {