doc: fix markdown headers in proxyconfig (#1068)
doc: fix markdown headers in proxyconfig (#1068)


kasubram/vsts-agent,lkillgore/vsts-agent,lkillgore/vsts-agent,Microsoft/vsts-agent,Microsoft/vsts-agent,Microsoft/vsts-agent,kasubram/vsts-agent,kasubram/vsts-agent,Microsoft/vsts-agent,kasubram/vsts-agent,lkillgore/vsts-agent,lkillgore/vsts-agent