Update about.md
Update about.md

fix to html

Former-commit-id: 5d00f9bd3c103778176f59469f02f9f465834413 [formerly 7011544e56e2d1ab5e25547f01da9d434f40b62d]
Former-commit-id: 58da6916a954a611fffd01d9f5db2eef71fe06c3
LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io