[COMPLIANCE] Update MPL 2.0 LICENSE (#338)

Co-authored-by: hashicorp-copywrite[bot] <noreply@hashicorp.com>
diff --git a/LICENSE b/LICENSE
index a612ad9..c121cee 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,3 +1,5 @@
+Copyright (c) 2020 HashiCorp, Inc.
+
 Mozilla Public License Version 2.0
 ==================================