Use of deprecated `--exclude-mail` flag of lychee

[thomas-zahner]

Just a little heads-up. You seem to be using the deprecated flag --exclude-mail of lychee. With the next release the flag might be removed, so your invocation of lychee will exit with an error.

You're using lycheeverse/lychee-action@master in your pipeline. I recommend switching to a specific released version to prevent similar issues in the future.

See: https://github.com/andkret/Cookbook/blob/e6e0083e00bcd765cb3120db3e54afe8bdedff2e/.github/workflows/linkchecker.yml#L17