[RFC] Enable GitHub action to test the patches as early and as often as possible

[coiby]

This patch set enables GitHub Action to test the patches whenever there is a pull request (PR) or a change to the PR. By testing the patches as early and as often as possible, we can prevent problems or catch problems early.

Four kinds of tests will be triggered automatically,

• Static analysis run by shellcheck
• Unit tests run by ShellSpec
• Integration tests
  • nfs-kdump
  • nfs-early-kdump,
  • ssh-kdump
  • local-kdump
  • lvm2-thinp-kdump