0.8.0 Bug: OS error: Permission denied
After running `choosenim update self`, `choosenim update devel`, and `choosenim devel`, I get the following error:
```
$ nim
     Error: Spawning of process failed. (Error was: Additional info: "Could not find command: \'/home/tandy/.choosenim/toolchains/nim-#devel/bin/nim\'. OS error: Permission denied")
      Info: If unexpected, please report this error to https://github.com/dom96/choosenim
```

I managed to fix the error by running `sudo chmod +x ~/.choosenim/toolchains/nim-#devel/bin/nim`.