Attempt to fix CI is failing due to a regression in Go 1.10.6 / 1.11.3 (see https://github.com/golang/go/issues/29241)
```
package github.com/containernetworking/plugins/...: github.com/containernetworking/plugins/...: invalid import path: malformed import path "github.com/containernetworking/plugins/...": double dot
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
