Add Cory Snider (corhere) as maintainer
Cory has actively participated in the project for many months, assisted in several
security advisories, code review, and triage, and (in short) already acted a
maintainer for some time (thank you!).
I nominated Cory as a maintainer per e-mail, and we reached quorum, so opening
this pull request to (should he choose to accept it) be added as a maintainer.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>