fix: use localStorage instead of sessionStorage to keep state

[revir]

Hi, thanks for this useful library. I found that sessionStorage is cleared on Firefox as soon as the current location is changed to the authorizing website. So I use localStorage instead. How do you think?

[bpedroza]

This PR is not the correct place to discuss the issue. Please continue discussion in an issue I opened - #5

[revir]

Oh really? I use it in my project https://github.com/pnlpal/dictionaries, and follows your guidelines to replace the current tab's history to authorize. No new window or tab. I guess it's a bug, but the firefox document doesn't clarify when to clear the session storage. my env is Firefox 82.0.2-1 on Manjaro Linux.

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-------------- *River* Bryan <notifications@github.com> 于2020年12月1日周二 下午10:12写道：

I tested in firefox, and this is not the case. Are you doing something else with your flow? The sessionStorage data is not persisted across tabs, but it is persisted in the same tab. Are you opening a new window to authorize or something? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAYZ6QQQ7CLBHAHB36UR7OLSST2UDANCNFSM4UIO4JHA> .

[bpedroza]

Please, use the issue I created to discuss. I am closing this PR until more discussion is had to make a decision.