Switch to official Vultr API library (#529)

* vultr: Switched to official API library (closes #528)

* vultr: Renamed vultr.VultrApi to vultr.Provider

* vendor: Updated govultr

vendor/github.com/vultr/govultr/api.go

@@ -0,0 +1,44 @@
+package govultr
+
+import (
+	"context"
+	"net/http"
+)
+
+// APIService is the interface to interact with the API endpoint on the Vultr API
+// Link: https://www.vultr.com/api/#auth
+type APIService interface {
+	GetInfo(ctx context.Context) (*API, error)
+}
+
+// APIServiceHandler handles interaction with the API methods for the Vultr API
+type APIServiceHandler struct {
+	client *Client
+}
+
+// API represents Vultr API information
+type API struct {
+	ACL   []string `json:"acls"`
+	Email string   `json:"email"`
+	Name  string   `json:"name"`
+}
+
+// GetInfo Vultr API auth information
+func (a *APIServiceHandler) GetInfo(ctx context.Context) (*API, error) {
+	uri := "/v1/auth/info"
+
+	req, err := a.client.NewRequest(ctx, http.MethodGet, uri, nil)
+
+	if err != nil {
+		return nil, err
+	}
+
+	api := new(API)
+	err = a.client.DoWithContext(ctx, req, api)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return api, nil
+}