add healthcheck

lua/zellij-nav/health.lua

@@ -0,0 +1,13 @@
+local M = {}
+
+M.check = function()
+  vim.health.report_start("zellij-nav.nvim")
+  local version = vim.fn.system("zellij --version")
+  if vim.v.shell_error ~= 0 then
+    vim.health.report_error("zellij executable not found in user's path")
+  else
+    vim.health.report_ok("found zellij version " .. string.gsub(version, "zellij ", ""))
+  end
+end
+
+return M