Caching dependencies to speed workflows

[sophia-guo]

Run-aqa on windows depends on the installation of cygwin and corresponding packages installed by cygwin.

Jobs on GitHub-hosted runners start in a clean virtual environment and must download dependencies each time, causing increased network utilization, longer runtime, and increased cost. To help speed up the time it takes to recreate these files, GitHub can cache dependencies you frequently use in workflows. https://docs.github.com/en/actions/configuring-and-managing-workflows/caching-dependencies-to-speed-up-workflows

We'd like to use the caching to preinstall cygwin and corresponding packages required. Howevereach packages will be installed in specified directory. When using the caching first specified directory is tar-ed and restore the cached files to the path you configure. That is the linking setup when install the packages cann't be relinked and installed package which is in the different path from cygwin will not be restored.

If the dependencies will be installed to specified path using caching may help. If dependencies will be installed scattered in different path caching may not help.