Cannot import modules in `.nimble` during `nimble install`
`nimble install nimsutils` fails with the following error:
```
Downloading https://github.com/FyraLabs/nimsutils using git
   Warning: The package has no tagged releases, downloading HEAD instead.
  Verifying dependencies for nimsutils@0.1.0
 Installing nimsutils@0.1.0
       Tip: 3 messages have been suppressed, use --verbose to show them.
nimble.nim(399)          packageExists

    Error:  The package inside "/home/mado/.nimble/pkgs2/nimsutils-0.1.0-3d97d4dd06c39f7943ddb0b1dd28b05136077e63" is invalid.
  Details:  Could not read package info file in /home/mado/.nimble/pkgs2/nimsutils-0.1.0-3d97d4dd06c39f7943ddb0b1dd28b05136077e63/nimsutils.nimble;
        ...   Reading as ini file failed with: 
        ...     Invalid section: .
        ...   Evaluating as NimScript file failed with: 
        ...     /home/mado/.nimble/pkgs2/nimsutils-0.1.0-3d97d4dd06c39f7943ddb0b1dd28b05136077e63/nimsutils.nimble(1, 11) Error: cannot open file: src/nimsutils
        ... printPkgInfo() failed.
```
However, if you run `nimble` inside the [repository](https://github.com/FyraLabs/nimsutils) directly, it works absolutely fine.

Since I can't find any docs saying you aren't allowed to import things in the `.nimble` file, I feel like this should be a bug from `nimble install`.