Converting HEIC to other formats

HI,
The `convert` utility is working great!

However, it fails to convert HEIC files.

```bash
$ convert IPAD-Photo\ 2.HEIC i.jpeg
convert: no decode delegate for this image format `HEIC' @ error/constitute.c/ReadImage/573.
convert: no images defined `i.jpeg' @ error/convert.c/ConvertImageCommand/3303.
```

I saw HEIC in the repo in imagemagick manual page: https://github.com/holzschu/a-shell/search?q=heic

I also tried a couple of Python solutions.

- https://pypi.org/project/pyheif/ Failed to install
- https://pypi.org/project/heic-to-jpg/ installed but fails to convert

```bash

$ heic-to-jpg -s IPAD-Photo.HEIC
which: command not found
Program 'convert' not found!
```
FFMPeg also currently does not support HEIC conversion.

Various articles suggest that Imagemagick works: https://blog.wplauncher.com/convert-heic-to-jpg-on-mac/
Another resource using a different solution: https://github.com/libvips/libvips

While not really a deal breaker or urgent issue, I just wanted to put this up here.

Aside - I get a similar warning for JPEG -> PDF too, but that works out okay. The generated pdf is perfect.

```bash

$ convert Image-2.png Im.pdf
convert: delegate library support not built-in `Im.pdf' (ZLIB) @ error/pdf.c/WritePDFImage/1556.
```