Fix #4836 (Switch to new Gandi LiveDNS API)

[rparenton]

1. Updated LiveDNS API URL for the new API
2. Updated authorization header syntax to allow deprecated API Keys to work with the new API

[github-actions]

Welcome
Please make sure you've read our DNS API Dev Guide and DNS-API-Test.
Then reply on this message, otherwise, your code will not be reviewed or merged.
We look forward to reviewing your Pull request shortly ✨
注意: 必须通过了 DNS-API-Test 才会被 review. 无论是修改, 还是新加的 dns api, 都必须确保通过这个测试.

[rparenton]

Welcome Please make sure you've read our DNS API Dev Guide and DNS-API-Test. Then reply on this message, otherwise, your code will not be reviewed or merged. We look forward to reviewing your Pull request shortly ✨ 注意: 必须通过了 DNS-API-Test 才会被 review. 无论是修改, 还是新加的 dns api, 都必须确保通过这个测试.

I have read the linked guides. Do I need to setup DNS API Test since this is just a fix and not a new DNS API?

[Neilpang]

yes

[rparenton]

Will create a new pull request once I have DNS API Test running