nim says "invalid package name"
I always cloned latest nim source and compiled in MSYS2+MingW64 on windows 10 64 bits. Everything is OK months ago. But now, something weired happened
1. first, the version of `nim.exe` and `nimble.exe`
```
$ nim --v
Nim Compiler Version 1.5.1 [Windows: amd64]
Compiled at 2021-06-26
Copyright (c) 2006-2021 by Andreas Rumpf

git hash: 39fbf3c84bd83613407e22b3de215d9a221b9422
active boot switches: -d:release


$ nimble --v
nimble v0.13.1 compiled at 2021-09-15 06:36:34
git hash: 795704833ddfd0cdaefb45c60551d3ea205279ef
```

2. I delete `C:\Users\USER\.nimble\` totally

3. the new `nim` compiler can compile the following `a.nim` without problem

```
# a.nim
echo 1
```

the processing:
```
$ nim c -r a
Hint: used config file 'E:\msys64\home\USER\_nim\nim\config\nim.cfg' [Conf]
Hint: used config file 'E:\msys64\home\USER\_nim\nim\config\config.nims' [Conf]
...................
CC: stdlib_digitsutils.nim
CC: stdlib_assertions.nim
CC: stdlib_dollars.nim
CC: stdlib_io.nim
CC: stdlib_system.nim
CC: a.nim
Hint:  [Link]
Hint: gc: refc; opt: none (DEBUG BUILD, `-d:release` generates faster code)
26554 lines; 1.454s; 31.953MiB peakmem; proj: a; out: Z:\a.exe [SuccessX]
Hint: Z:\a.exe  [Exec]
1
```

4. `nimble` can install package
```
$ nimble install listsv
    Prompt: No local packages.json found, download it from internet? [y/N]
y
    Answer: Downloading Official package list
    Success Package list downloaded.
Downloading https://github.com/srwiley/listsv.git using git
   Warning: The package has no tagged releases, downloading HEAD instead.
  Verifying dependencies for listsv@0.1.0
 Installing listsv@0.1.0
  Success:  listsv installed successfully.

```

5. then the strange happens
```
$ rm a.exe

$ nim c -r a
E:\msys64\home\USER\_nim\nim\config\nim.cfg(51, 1) Error: invalid package name: C:\Users\USER\.nimble\pkgs\listsv-0.1.0-a6dfb9de705011f6d04902493cac04a4f20a0435
```



I found that the new-installed package is under `C:\Users\USER\.nimble\pkgs\listsv-0.1.0-a6dfb9de705011f6d04902493cac04a4f20a0435\` directory. However, I remember it should be `listsv-0.1.0`. So what happened to `nimble`?



thanks
