Update navigation.yml
Update navigation.yml

linking to current instructors list

Former-commit-id: 12fbc06aac777ac3932d754405b65a131094797b [formerly d185edd925edc7abe2f76ce73da64b8d9f6c39ad]
Former-commit-id: b96cb3c5f3d2b03880270306c80131474eb2f694
LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io