vendor: add cfssl dependency

vendor/github.com/cloudflare/cfssl/info/info.go

@@ -0,0 +1,15 @@
+// Package info contains the definitions for the info endpoint
+package info
+
+// Req is the request struct for an info API request.
+type Req struct {
+	Label   string `json:"label"`
+	Profile string `json:"profile"`
+}
+
+// Resp is the response for an Info API request.
+type Resp struct {
+	Certificate  string   `json:"certificate"`
+	Usage        []string `json:"usages"`
+	ExpiryString string   `json:"expiry"`
+}