Update cxxopts from 3.0 to 3.1.1

!android-nn-driver:9431

Signed-off-by: Jim Flynn <jim.flynn@arm.com>
Change-Id: I58143445b5c5cf2aafd0838156c9543adce21e6a
diff --git a/third-party/cxxopts/CHANGELOG.md.license b/third-party/cxxopts/CHANGELOG.md.license
index bf1b5b5..2a9007a 100644
--- a/third-party/cxxopts/CHANGELOG.md.license
+++ b/third-party/cxxopts/CHANGELOG.md.license
@@ -1,4 +1,4 @@
 #
-# Copyright (c) 2014 Jarryd Beck
+# Copyright (c) 2014-2022 Jarryd Beck
 # SPDX-License-Identifier: MIT
 #