d/rules: Add required build targets

Section 4.9 of the Debian Policy[0] requires the following missing targets: build-arch and build-indep. This is only an issue with newer lintian as debian-rules-missing-required-target has been bumped to an error in lintian[1] causing the crimson archive to reject the upload.

[0] https://www.debian.org/doc/debian-policy/ch-source.html#main-building-script-debian-rules [1] https://lintian.debian.org/tags/debian-rules-missing-required-target