[COMPLIANCE] Add Copyright and License Headers (#2242)

Co-authored-by: hashicorp-copywrite[bot] <110428419+hashicorp-copywrite[bot]@users.noreply.github.com>

addons/api/addon/utils/hash-code.js

@@ -1,3 +1,8 @@
+/**
+ * Copyright (c) HashiCorp, Inc.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
 /**
  * Takes an object and gets the JSON stringified version of it to be converted
  * to a hash code. Taken from https://stackoverflow.com/a/8076436