feat: add bats tests, docs (#139)

* fix(test): ensure bats file list uses xargs

* docs(readme): use yarn for testing instructions

* fix(test): ensure pipelines fail properly

* docs(alias): fix table header

---------

Signed-off-by: Ismo Vuorinen <ismo@ivuorinen.net>

tests/x-gh-get-latest-version.bats

@@ -0,0 +1,7 @@
+#!/usr/bin/env bats
+
+@test "x-gh-get-latest-version help" {
+  run bash local/bin/x-gh-get-latest-version --help
+  [ "$status" -eq 1 ]
+  [[ "$output" == "Usage: x-gh-get-latest-version"* ]]
+}