feat: add dlv as dep

lua/gopher/config.lua

···
       gotests = "gotests",
       impl = "impl",
       iferr = "iferr",
+      dlv = "dlv",
     },
   },
 }

lua/gopher/health.lua

···
       { bin = c.gomodifytags, help = "required for modify struct tags" },
       { bin = c.impl, help = "required for interface implementing" },
       { bin = c.gotests, help = "required for test(s) generation" },
+      { bin = c.dlv, help = "required for debugger(nvim-dap)" },
     },
   },
 }

lua/gopher/installer.lua

···
   impl = "github.com/josharian/impl",
   gotests = "github.com/cweill/gotests/...",
   iferr = "github.com/koron/iferr",
+  dlv = "github.com/go-delve/delve/cmd/dlv",
 }
 
 ---@param pkg string