About defaulting the `hShift = 1` option

[takahirom]

It appears that we can mitigate OS-specific differences by using dropbox/differ's hShift option. The question is whether this should be set as the default option. Without using hShift, the diffs look like this: https://github.com/takahirom/roborazzi/pull/433 When using hShift=1, the diffs appear as follows (There are still differences when using dumps and scale options, as well as for desktop screenshots. However, for typical use cases, these differences will largely disappear. https://github.com/takahirom/roborazzi/pull/456