Add support for proxy via environment variables. Not completely sure this works because I don't have a real test environment, but this is what other providers have done. Closes #48

Author: mikejihbe

provider.go

@@ -5,6 +5,7 @@ package main
 import (
 	"errors"
 	"fmt"
+	"net/http"
 
 	"github.com/MustWin/baremetal-sdk-go"
 	"github.com/oracle/terraform-provider-baremetal/core"
@@ -186,6 +187,9 @@ func providerConfig(d *schema.ResourceData) (client interface{}, err error) {
 		func(o *baremetal.NewClientOptions) {
 			o.UserAgent = fmt.Sprintf("baremetal-terraform-v%s", baremetal.SDKVersion)
 		},
+		func(o *baremetal.NewClientOptions) {
+			o.Transport = &http.Transport{Proxy: http.ProxyFromEnvironment}
+		},
 	}
 
 	if hasKey && privateKeyBuffer != "" {