Spec release with filetype and schema fields

A previous commit updated the specification to add filetype and schema
fields, but no release was made.  This commit triggers the creation of
the new tag and run the release process (publish new JSON schema).

(This is an empty commit)

RELEASE-TAG: spec_v1.4

Signed-off-by: Gunnar Andersson <[email protected]>

Author: gunnar-mb