[wontfix] choosenim 0.16.0 works but nothing before 0.16.0 works, eg error: "Version 0.15.0 does not exist"
choosenim 0.16.0 works but nothing before 0.16.0 works, eg: Version 0.15.0 does not exist

This makes it really hard to find regressions (eg I'm trying to find when iterator composition worked, cf https://github.com/nim-lang/Nim/issues/8188 and https://github.com/def-/nim-iterutils/issues/4) 

choosenim 0.15.0
```
Downloading Nim 0.15.0 from nim-lang.org
[#                                                 ] 0mb 0kb/s
       Tip: 1 messages have been suppressed, use --verbose to show them.
     Error: choosenim.nim(206)       choosenim
        ... choosenim.nim(187)       performAction
        ... choosenim.nim(89)        choose
        ... choosenim.nim(72)        chooseVersion
        ... choosenim.nim(34)        installVersion
        ... download.nim(252)        download
        ... Version 0.15.0 does not exist.
```

I also tried:
choosenim  '#v0.15.0'
(after removing  /Users/timothee/.choosenim/downloads/master.tar.gz as a workaround for caching issue I just mentioned in https://github.com/dom96/choosenim/issues/65, to avoid a potentially wrong cache hit: "Info: /Users/timothee/.choosenim/downloads/master.tar.gz already downloaded")


```
Downloading Nim v0.15.0 from GitHub
      Info: /Users/timothee/.choosenim/downloads/v0.15.0.tar.gz already downloaded
 Extracting v0.15.0.tar.gz
   Building Nim #v0.15.0
   Warning: Building from latest C sources. They may not be compatible with the Nim version you have chosen to install.
Downloading Nim C sources from GitHub
[##################################################] 100.0% 0kb/s
 Extracting master.tar.gz
   Building C sources
   Building koch
 Exception: choosenim.nim(206)       choosenim
        ... choosenim.nim(187)       performAction
        ... choosenim.nim(89)        choose
        ... choosenim.nim(72)        chooseVersion
        ... choosenim.nim(46)        installVersion
        ... builder.nim(91)          build
        ... builder.nim(43)          buildCompiler
        ... utils.nim(19)            doCmdRaw
        ... Execution failed with exit code 1
        ... Command: ./bin/nim c koch
        ... Output: Hint: used config file '/Users/timothee/.choosenim/toolchains/nim-#v0.15.0/config/nim.cfg' [Conf]
        ... Hint: used config file '/Users/timothee/.config/nim.cfg' [Conf]
        ... Hint: used config file 'koch.nim.cfg' [Conf]
        ... Hint: system [Processing]
        ... lib/system.nim(392, 27) Error: type mismatch: got <type int>
        ... but expected one of:
        ... proc high[T](x: T): T
        ... expression: high(int)
   Cleaning failed build
     Error: choosenim.nim(206)       choosenim
        ... choosenim.nim(187)       performAction
        ... choosenim.nim(89)        choose
        ... choosenim.nim(72)        chooseVersion
        ... choosenim.nim(46)        installVersion
        ... builder.nim(100)         build
        ... Build failed
```

