Update teach.md
Update teach.md

add workshops link

Former-commit-id: 2a382dc42d7c27b80e3b686587e5d353210b314e [formerly 6e22dfee0b34d5d420e48cd2817d9d544ca7ea21]
Former-commit-id: 2dbdb8b297041623e047653c09a6095ad2be5549
LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io