setuptools_scm required for install, but not set up as a requirement

[brabulla]

Description

setuptools-scm is required for installing both the resilient-circuits and the resilient package, but this is not reflected in the list of required packages. This causes an offline install to fail, if there is no internet connectivity, and using a pre-downloaded list of packages produced by executing
pip download resilient-circuits

This command will not produce any version of the package setuptools-scm, and the install on an offline system will fail, with the following message:

ERROR: Could not find a version that satisfies the requirement setuptools_scm (from versions: none)
ERROR: No matching distribution found for setuptools_scm 

Describe How to Reproduce

1. Produce a list of installable packages required for installing resilient-circuits offline, with pip download resilient-circuits
2. Copy all produced files to a target system without network, and any access to python package repositories
3. Execute an offline pip install of the resilient-circuits package, that uses the pre-loaded packages to find dependencies: pip install --no-index --find-links file:///path/to/packages resilient-circuits-XX.X.XXX.tar.gz

Proposed fix

Include setuptools_scm in the list of required packages. This will make pip recognize it as a dependency, and possibly fix this issue.