Add REUSE compliance checker to CI

LICENSE.md

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+Copyright 2015-2023 The Khronos Group Inc.
+
+Files in this repository fall under one of these licenses:
+
+- `Apache-2.0`
+- `MIT`
+
+Note: With the exception of `parse_dependency.py` the files using `MIT` license
+also fall under `Apache-2.0`. Example:
+
+```
+SPDX-License-Identifier: Apache-2.0 OR MIT
+```
+
+Full license text of these licenses is available at:
+
+  * Apache-2.0: https://opensource.org/licenses/Apache-2.0
+  * MIT: https://opensource.org/licenses/MIT