opam: update version constraints

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Release 0.9.9

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #27 from djs55/release.0.9.9

Release.0.9.9