fix jvm.cpu.time metric name

Author: SylvainJuge

instrumentation/jmx-metrics/library/src/main/resources/jmx/rules/jvm.yaml

@@ -74,7 +74,7 @@ rules:
         desc: Number of processors available to the Java virtual machine.
       # jvm.cpu.time
       ProcessCpuTime:
-        metric: jvm.cpu.time
+        metric: cpu.time
         type: counter
         sourceUnit: ns
         unit: s