update github.com/vishvananda/netlink to v1.3.0

There seems to be one change[1] which breaks our tests, the route Dst field
is no longer nil for a default route but rather the empty ipnet, i.e.
0.0.0.0/0 and ::/0 so fix that up in our code.

[1] https://github.com/vishvananda/netlink/pull/852

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

vendor/github.com/vishvananda/netlink/chain.go

@@ -0,0 +1,22 @@
+package netlink
+
+import (
+	"fmt"
+)
+
+// Chain contains the attributes of a Chain
+type Chain struct {
+	Parent uint32
+	Chain  uint32
+}
+
+func (c Chain) String() string {
+	return fmt.Sprintf("{Parent: %d, Chain: %d}", c.Parent, c.Chain)
+}
+
+func NewChain(parent uint32, chain uint32) Chain {
+	return Chain{
+		Parent: parent,
+		Chain:  chain,
+	}
+}