Moving to SetOut and SetErr for Cobra

SetOutput is deprecated. This causes it to fail linting.

Signed-off-by: Matt Farina <matt@mattfarina.com>
(cherry picked from commit b689ff203e)

cmd/helm/require/args_test.go

@@ -71,7 +71,8 @@ func runTestCases(t *testing.T, testCases []testCase) {
 				Args: tc.validateFunc,
 			}
 			cmd.SetArgs(tc.args)
-			cmd.SetOutput(io.Discard)
+			cmd.SetOut(io.Discard)
+			cmd.SetErr(io.Discard)
 
 			err := cmd.Execute()
 			if tc.wantError == "" {