Replace hardcoded HTTP-links in lessons page (#592)
Replace hardcoded HTTP-links in lessons page (#592)

Co-authored-by: François Michonneau <4bff5603797561c3fedccb447c96a82cfbf31b51@gmail.com>
datacarpentry/datacarpentry.github.io,datacarpentry/datacarpentry.github.io,datacarpentry/datacarpentry.github.io