Fails to create new post when selecting file instead of folder

[johnhforrest]

Just tried to install this and it doesn't work. I see the "New post" option in the context menu but entering a file name and pressing enter does nothing.

[johnhforrest]

Found the bug. If you use "new post" on a file instead of a folder, it breaks the path:

// This becomes the full path of a file, could be /path/filename.md
const dirName = uri.fsPath;

Will send a PR when I have some time