On Arch Linux, imagemagick is currently at 7.1.0. I tried increasing the
max version and the version used in the Dockerfile to 7.1 and it appears
to compile and tests pass. Version used for local testing:
```
Linux 5.12.12-arch1-1 #1 SMP PREEMPT Fri, 18 Jun 2021 21:59:22 +0000 x86_64 GNU/Linux
Version: ImageMagick 7.1.0-1 Q16 x86_64 2021-06-21 https://imagemagick.org
Copyright: (C) 1999-2021 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC HDRI Modules OpenMP(4.5)
Delegates (built-in): bzlib cairo djvu fontconfig freetype heic jbig jng jp2 jpeg lcms lqr ltdl lzma openexr pangocairo png raqm raw rsvg tiff webp wmf x xml zip zlib
```
