Markdown links checker keeps failing with 403s on docs.github.com

[andyblundell]

These are false negatives - it seems to be that docs.github now requires specific headers or it rejects with 403. Adding this to the checker's config file (rather than excluding the links in question from the check) might fix this

"httpHeaders": [
{
"urls": ["https://docs.github.com/"],
"headers": {
"Accept-Encoding": "zstd, br, gzip, deflate"
}
}
]