Build failure for master branch

[jeesmon]

Docker build is failing for last few commits to master. Can it be fixed please so that we can get latest build with vulnerability fixes?

Pipeline link: https://app.circleci.com/pipelines/github/prometheus/pushgateway/937/workflows/967a5dcb-a3c6-4cf0-a4d4-f5c97934892a/jobs/2542

Error:

 => => extracting sha256:3d9e5d46732a2c40e9c46d378f72940a24d14671c0a76cb2  0.0s
 => [2/4] COPY --chown=nobody:nobody .build/linux-armv7/pushgateway /bin/  0.1s
 => ERROR [3/4] RUN mkdir -p /pushgateway && chown nobody:nobody /pushgat  0.2s
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 > [3/4] RUN mkdir -p /pushgateway && chown nobody:nobody /pushgateway:
#5 0.137 /bin/sh: mkdir: Function not implemented
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process "/bin/sh -c mkdir -p /pushgateway && chown nobody:nobody /pushgateway" did not complete successfully: exit code: 127
make: *** [Makefile.common:223: common-docker-armv7] Error 1