ci: Remove tag dependency for build-previous-qemu

ci: Remove tag dependency for build-previous-qemu

The new build-previous-qemu job relies on QEMU release tag being present,
while that may not be always true for personal git repositories since by
default tag is not pushed.  The job can fail on those CI kicks, as reported
by Peter Maydell.

Fix it by fetching the tags remotely from the official repository, as
suggested by Dan.

[1] https://lore.kernel.org/r/ZcC9ScKJ7VvqektA@redhat.com

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Suggested-by: "Daniel P. Berrangé" <berrange@redhat.com>
Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com>
Link: https://lore.kernel.org/r/20240207005403.242235-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>