Wiki page `Building on Windows` needs updated wget for zlib

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### Expected behavior
`wget http://zlib.net/zlib1211.zip` should download file

### Actual behavior
```
$ wget http://zlib.net/zlib1211.zip
--2022-08-03 08:20:15-- http://zlib.net/zlib1211.zip
Resolving zlib.net (zlib.net)... 85.187.148.2
Connecting to zlib.net (zlib.net)|85.187.148.2|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2022-08-03 08:20:16 ERROR 404: Not Found.
```

### Steps to reproduce the behavior
See above.

Root cause is that [zlib.net](https://zlib.net/) AFAIK does not provide a link for the current release. Only the latest release is available and the URL requires the specific version number. So each time zlib.net updates, the instruction needs to be updated.

---

Note: I am no expert with wget or cURL but tried to find a solution using each.

While not a perfect workaround this is more resilient to change.

Note: When following the instructions two shells were used.
* Developer Command Prompt for VS 2022
* MSYS2 MinGW x64 (thus the $ before the command)

The wget command was run under MSYS2 as installing wget on Windows just was not worth the trouble.

```
$ wget --no-verbose --recursive --no-parent --no-host-directories --level=1 -A 'zlib*.zip' http://zlib.net/
$ unzip zlib*.zip
$ cd zlib-*/contrib/vstudio/vc14
```

The problem is it is still locally creating the empty directory `pigz`.
Also tried using cURL but that had a worse outcome.