community/py3-magic: fix check()

The mime types seems to have changed recently. Also the gzip output is
slightly different now.

The same patch fixes the tests on Arch Linux.
7 jobs for !10941 with py3-magic-check in 1 minute and 17 seconds
detached
Status Job ID Name Coverage
  Lint
passed #177256
x86_64 docker-alpine
lint

00:00:23

 
  Build
passed #177261
aarch64 ci-build docker-alpine
build-aarch64

00:00:29

passed #177262
armv7 ci-build docker-alpine
build-armv7

00:00:35

passed #177260
ppc64le ci-build docker-alpine
build-ppc64le

00:00:51

failed #177259
s390x ci-build docker-alpine
build-s390x

passed #177258
x86 ci-build docker-alpine
build-x86

00:00:28

passed #177257
x86_64 ci-build docker-alpine
build-x86_64

00:00:26

 
Name Stage Failure
failed
build-s390x Build There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job log