"docker: invalid reference format: repository name must be lowercase" in GNU Make 4

[e-t-k]

Running make run or make run-treehouse produces an error:

docker: invalid reference format: repository name must be lowercase.
See 'docker run --help'.
make: *** [Makefile:23: run-treehouse] Error 125

These commands worked in make v3.8 but no longer work in v4.3.
The problem is the line --user $$UID \.
This line needs to be replaced with --user $(shell id -u) \.

This has been fixed in branch https://github.com/UCSC-Treehouse/CARE/tree/e-t-k-patch-1 .
To clone: git clone https://github.com/UCSC-Treehouse/CARE.git --branch e-t-k-patch-1