Rename Mega-Linter to MegaLinter

[sanmai-NL]

[nvuillam]

There are maaaaany places where mega-linter is still used.... where do you still see it in documentation ?

[sanmai-NL]

The README and this repo's description on GitHub. Quite prominent. 😉

[nvuillam]

Would you like to make a PR ? :)

[nvuillam]

(this repo is synced from oxsecurity/megalinter )

[sanmai-NL]

It's very small and I can't change the GitHub description in a PR.