fixkey: downgrade to 2.0.5

[daeho-ro]

2.0.6 is gone away and cannot download, so downgrade to 2.0.5 and also change the livecheck to the header_match. This can be reverted after a new version released, maybe.

---

Important: Do not tick a checkbox if you haven’t performed its action. Honesty is indispensable for a smooth review process.

In the following questions <cask> is the token of the cask you're submitting.

After making any changes to a cask, existing or new, verify:

• The submission is for a stable version or documented exception.
• brew audit --cask --online <cask> is error-free.
• brew style --fix <cask> reports no offenses.

[bevanjkay]

I would rather downgrade without changing the livecheck and skip the livecheck on CI. I don't think it makes sense to change livecheck to fix temporary upstream issues.