Vendor update github.com/pkg/errors

vendor/github.com/pkg/errors/bench_test.go

@@ -15,6 +15,7 @@ func noErrors(at, depth int) error {
 	}
 	return noErrors(at+1, depth)
 }
+
 func yesErrors(at, depth int) error {
 	if at >= depth {
 		return New("ye error")
@@ -22,8 +23,11 @@ func yesErrors(at, depth int) error {
 	return yesErrors(at+1, depth)
 }
 
+// GlobalE is an exported global to store the result of benchmark results,
+// preventing the compiler from optimising the benchmark functions away.
+var GlobalE error
+
 func BenchmarkErrors(b *testing.B) {
-	var toperr error
 	type run struct {
 		stack int
 		std   bool
@@ -53,7 +57,7 @@ func BenchmarkErrors(b *testing.B) {
 				err = f(0, r.stack)
 			}
 			b.StopTimer()
-			toperr = err
+			GlobalE = err
 		})
 	}
 }