vendor: Update pfilter (fixes #4537)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4539

vendor/github.com/AudriusButkevicius/pfilter/conn.go

@@ -7,6 +7,9 @@ import (
 )
 
 type FilteredConn struct {
+	// Alignment
+	deadline atomic.Value
+
 	source   *PacketFilter
 	priority int
 
@@ -14,7 +17,6 @@ type FilteredConn struct {
 
 	filter Filter
 
-	deadline atomic.Value
 	closed   chan struct{}
 }
 

vendor/github.com/AudriusButkevicius/pfilter/filter.go

@@ -26,13 +26,14 @@ func NewPacketFilter(conn net.PacketConn) *PacketFilter {
 
 // PacketFilter embeds a net.PacketConn to perform the filtering.
 type PacketFilter struct {
+	// Alignment
+	dropped  uint64
+	overflow uint64
+
 	net.PacketConn
 
 	conns []*FilteredConn
 	mut   sync.Mutex
-
-	dropped  uint64
-	overflow uint64
 }
 
 // NewConn returns a new net.PacketConn object which filters packets based