chore(lib): Add pumba lib image for pod-cpu-hog (#314)

Signed-off-by: Udit Gaurav <udit.gaurav@mayadata.io>

charts/generic/pod-cpu-hog/experiment.yaml

@@ -37,7 +37,7 @@ spec:
     - /bin/bash
     env:
     - name: TOTAL_CHAOS_DURATION
-      value: '30'
+      value: '60'
     
     - name: CHAOS_INTERVAL
       value: '10'
@@ -54,9 +54,15 @@ spec:
     - name: RAMP_TIME
       value: ''
 
+    ## env var that describes the library used to execute the chaos
+    ## default: litmus. Supported values: litmus, pumba    
     - name: LIB
       value: 'litmus'
 
+    ## It is used in pumba lib only    
+    - name: LIB_IMAGE
+      value: 'gaiaadm/pumba'  
+
     - name: TARGET_POD
       value: ''