fix docker build

[wey-gu]

What type of PR is this?

• bug
• feature
• enhancement

What problem(s) does this PR solve?

Issue(s) number:

#188

Description:

qemu is needed for buildx to build docker image for arm64

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Dockerfile:5
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   3 |     COPY . /usr/src
   4 |     
   5 | >>> RUN cd /usr/src && apk add --no-cache git make && make
   6 |     
   7 |     FROM alpine
--------------------
ERROR: failed to solve: process "/dev/.buildkit_qemu_emulator /bin/sh -c cd /usr/src && apk add --no-cache git make && make" did not complete successfully: exit code: 2
Error: buildx failed with: ERROR: failed to solve: process "/dev/.buildkit_qemu_emulator /bin/sh -c cd /usr/src && apk add --no-cache git make && make" did not complete successfully: exit code: 2