one more readme rename fix.

Author: Codeslayer666

README.md

@@ -246,7 +246,7 @@ values:
 * `UPCLOUD_GO_SDK_TEST_PASSWORD` (the API password)
 * `UPCLOUD_GO_SDK_TEST_DELETE_RESOURCES` (either `yes` or `no`)
 
-To run the test suite, run `go test ./... -v -parallel 8`. If `UPCLOUD_GO_API_TEST_DELETE_RESOURCES` is set to `yes`,
+To run the test suite, run `go test ./... -v -parallel 8`. If `UPCLOUD_GO_SDK_TEST_DELETE_RESOURCES` is set to `yes`,
 all resources will be stopped and/or deleted after the test suite has run. Be careful which account you use for
 testing so you don't accidentally delete or your production resources!