deps: update github.com/cloudflare/cfssl to v1.3.4 (#4377)

This will unblock pre-issuance linting support by updating the
`github.com/cloudflare/cfssl` dependency to the `1.3.4` tag which
notably includes the zlint integration developed in
cloudflare/cfssl#1015

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/asaskevich/govalidator v0.0.0-20180720115003-f9ffefc3facf // indirect
 	github.com/beeker1121/goque v0.0.0-20170321141813-4044bc29b280
 	github.com/beorn7/perks v0.0.0-20160229213445-3ac7bf7a47d1 // indirect
-	github.com/cloudflare/cfssl v0.0.0-20190616170404-1bf3e59ec1cf
+	github.com/cloudflare/cfssl v0.0.0-20190716004220-2185c182e6ba
 	github.com/go-gorp/gorp v2.0.0+incompatible // indirect
 	github.com/go-sql-driver/mysql v0.0.0-20170715192408-3955978caca4
 	github.com/golang/mock v1.2.0

go.sum

@@ -15,6 +15,9 @@ github.com/cloudflare/cfssl v0.0.0-20190409034051-768cd563887f h1:+2gpkLTePKn3qD
 github.com/cloudflare/cfssl v0.0.0-20190409034051-768cd563887f/go.mod h1:yMWuSON2oQp+43nFtAV/uvKQIFpSPerB57DCt9t8sSA=
 github.com/cloudflare/cfssl v0.0.0-20190616170404-1bf3e59ec1cf h1:0/1jvWAjicn0BZTNnv5KLnf29+B01Yh1O0BMLrgOCb0=
 github.com/cloudflare/cfssl v0.0.0-20190616170404-1bf3e59ec1cf/go.mod h1:yMWuSON2oQp+43nFtAV/uvKQIFpSPerB57DCt9t8sSA=
+github.com/cloudflare/cfssl v0.0.0-20190716004220-2185c182e6ba h1:gI0EFi8pFYkjYBA3A78uFXRUzAx1pkYS1lVcsYdSZhE=
+github.com/cloudflare/cfssl v0.0.0-20190716004220-2185c182e6ba/go.mod h1:yMWuSON2oQp+43nFtAV/uvKQIFpSPerB57DCt9t8sSA=
+github.com/cloudflare/cfssl v0.0.0-20190726000631-633726f6bcb7 h1:Puu1hUwfps3+1CUzYdAZXijuvLuRMirgiXdf3zsM2Ig=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=