Create missing Directory entry in GitErrorCode

[nulltoken]

An error in #1202 build led us to discover we're missing a GitErrorCode entry mapping from GIT_EDIRECTORY. Let's fix this.

References:

• https://github.com/libgit2/libgit2/blob/master/include/git2/errors.h
• https://github.com/libgit2/libgit2sharp/blob/vNext/LibGit2Sharp/Core/GitErrorCode.cs

[rubberduck203]

Did PR #1208 close this? I went to grab it, but just now saw the PR.

[nulltoken]

Did PR #1208 close this?

@ckuhn203 Indeed. Thanks for the heads up!

[rubberduck203]

You're welcome @nulltoken! I'll see what else I can find to do.