CI: install python3-rfc3987
This gives us validation of the URIs used in our schemas. [Backport commit a816fcf4.] Signed-off-by:Vincent Stehlé <vincent.stehle@arm.com>
This gives us validation of the URIs used in our schemas. [Backport commit a816fcf4.] Signed-off-by:Vincent Stehlé <vincent.stehle@arm.com>