fixes build failure for aarch64
```
make rpm-docker GOARCH=arm64 GOOS=linux
+ /usr/lib/rpm/brp-compress
+ /usr/lib/rpm/brp-strip /usr/bin/strip
/usr/bin/strip: Unable to recognise the format of the input file `/build/src/artifacts/rpmbuild/BUILDROOT/zrepl-v0.3.0.38.g53028ed5-1.aarch64/usr/bin/zrepl'
error: Bad exit status from /var/tmp/rpm-tmp.g8Fdbs (%install)
Bad exit status from /var/tmp/rpm-tmp.g8Fdbs (%install)
```