annotations.md: Fix a small typo
annotations.md: Fix a small typo

Signed-off-by: Florian Woerner <e970bf2e7184df48ee879e539aae4b8267fd98d2@onmyown.io>

jonboulle/image-spec,jonboulle/image-spec,opencontainers/image-spec,opencontainers/image-spec