set coverage export format to lcov

Author: HossamSaberr

.smalltalk.ston

@@ -8,7 +8,8 @@ SmalltalkCISpec {
   ],
   #testing : {
     #coverage : {
-      #packages : [ 'Containers-Trie' ]
+      #packages : [ 'Containers-Trie' ],
+      #format : #lcov
     }
   }
 }