rename snapshot->snapshots pkg

Signed-off-by: Jess Valarezo <valarezo.jessica@gmail.com>

cmd/containerd/builtins_btrfs_linux.go

@@ -2,4 +2,4 @@
 
 package main
 
-import _ "github.com/containerd/containerd/snapshot/btrfs"
+import _ "github.com/containerd/containerd/snapshots/btrfs"

cmd/containerd/builtins_linux.go

@@ -3,5 +3,5 @@ package main
 import (
 	_ "github.com/containerd/containerd/linux"
 	_ "github.com/containerd/containerd/metrics/cgroups"
-	_ "github.com/containerd/containerd/snapshot/overlay"
+	_ "github.com/containerd/containerd/snapshots/overlay"
 )

cmd/containerd/builtins_unix.go

@@ -3,5 +3,5 @@
 package main
 
 import (
-	_ "github.com/containerd/containerd/snapshot/naive"
+	_ "github.com/containerd/containerd/snapshots/naive"
 )

cmd/containerd/builtins_windows.go

@@ -1,6 +1,6 @@
 package main
 
 import (
-	_ "github.com/containerd/containerd/snapshot/windows"
+	_ "github.com/containerd/containerd/snapshots/windows"
 	_ "github.com/containerd/containerd/windows"
 )