helm: Fix documentation URL for v1.10
helm: Fix documentation URL for v1.10

v1.10 will need more than the first 3 digits of the version semver, it
will need the full $major.$minor. Fix this up.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

tgraf/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,tgraf/cilium