Add 1 git-crypt collaborator

[mtac50]

What

• Added Michael to git-crypt

Checklist

Before you ask people to review this PR:

• Tests and linters should be passing
• Github should not be reporting conflicts; you should have recently run git rebase master.
• Avoid mixing whitespace changes with code changes in the same commit. These make diffs harder to read and conflicts more likely.
• You should have looked at the diff against master and ensured that nothing unexpected is included in your changes.
• You should have checked that the commit messages say why the change was made.