Broken link for "version selection" in SPEC

[adriancuadrado]

https://github.com/containernetworking/cni/blob/main/SPEC.md#configuration-format

• cniVersions (string list): List of all CNI versions which this configuration supports. See version selection below.

[LionelJouin]

must be fixed in https://github.com/containernetworking/cni.dev/blob/main/content/docs/spec.md too