update to latest bbolt

with two changes, both not resulting in different behaviour for us.

vendor/go.etcd.io/bbolt/unsafe.go

@@ -1,7 +1,6 @@
 package bbolt
 
 import (
-	"reflect"
 	"unsafe"
 )
 
@@ -26,14 +25,3 @@ func unsafeByteSlice(base unsafe.Pointer, offset uintptr, i, j int) []byte {
 	// all), so this is believed to be correct.
 	return (*[maxAllocSize]byte)(unsafeAdd(base, offset))[i:j:j]
 }
-
-// unsafeSlice modifies the data, len, and cap of a slice variable pointed to by
-// the slice parameter.  This helper should be used over other direct
-// manipulation of reflect.SliceHeader to prevent misuse, namely, converting
-// from reflect.SliceHeader to a Go slice type.
-func unsafeSlice(slice, data unsafe.Pointer, len int) {
-	s := (*reflect.SliceHeader)(slice)
-	s.Data = uintptr(data)
-	s.Cap = len
-	s.Len = len
-}