Update dns_cyon plugin

[JazzMalar]

• Read the Guidelines
• GitHub Actions run successfully

Changes

• Updated api field names as described in Updates dns_cyon txt_body and adds validation #6097
• Reimplemented env change check in separate function for readability
• Added support for OpenBSD by replacing propriety regex functions with BREs

Fixes #6127

[github-actions]

Welcome
First thing: don't send PR to the master branch, please send to the dev branch instead.
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.
Please also make sure to add/update the usage here: https://github.com/acmesh-official/acme.sh/wiki/dnsapi2
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.

[JazzMalar]

Welcome First thing: don't send PR to the master branch, please send to the dev branch instead. 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. Please also make sure to add/update the usage here: https://github.com/acmesh-official/acme.sh/wiki/dnsapi2 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.

• Pull Request on dev branch
• Read and adhered to the guidelines
• DNS-API tests were successful