add qemu before release

[mohammedalics]

Why?

This PR is to fix the issue in releasing multi-platform docker images.

See issue: https://app.circleci.com/pipelines/github/seznam/slo-exporter/384/workflows/932fb8ac-8631-4d2d-a48b-9dbc083055d2/jobs/1603?invite=true#step-103-96

#6 ERROR: process "/bin/sh -c apt-get update && apt-get install ca-certificates -y && apt-get clean" did not complete successfully: exit code: 1
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 > [2/5] RUN apt-get update && apt-get install ca-certificates -y && apt-get clean:
0.237 exec /bin/sh: exec format error
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Dockerfile:3
--------------------
   1 |     FROM debian:stable-slim
   2 |     
   3 | >>> RUN apt-get update && apt-get install ca-certificates -y && apt-get clean
   4 |     
   5 |     COPY slo_exporter  /slo_exporter/
--------------------
ERROR: failed to solve: process "/bin/sh -c apt-get update && apt-get install ca-certificates -y && apt-get clean" did not complete successfully: exit code: 1

Learn more at https://goreleaser.com/errors/docker-build

make: *** [Makefile:75: release] Error 1

Exited with code exit status 2

Solution

Adding qemu

As mentioned in goreleaser documentation here:

For buildx to work properly, you'll need to install qemu