Update heapdump dependency to v0.3.7
Update heapdump dependency to v0.3.7

v0.3.7 is compatible with node v4.1.

wikimedia/mediawiki-services-restbase,wikimedia/hyperswitch,milimetric/restbase,wikimedia/mediawiki-services-restbase,milimetric/restbase,d00rman/restbase,cscott/restbase,gwicke/restbase,gwicke/restbase,Pchelolo/restbase,inverno/restbase,wikimedia/restbase,cscott/restbase,eevans/restbase,eevans/restbase,wikimedia/restbase,d00rman/restbase,inverno/restbase,Pchelolo/restbase