Fix caching of submodule links for shas with dashes
What does this MR do?
Currently, when I try to view a tree of files with submodules for a signed-commits
branch of gitlab-test
project locally with Vue
file list enabled, an exception is raised, because Ruby
doesn't allow instance variables with dashes
This MR uses a simple hash to memoize submodule links by ref instead of the strong memoization