fix not being able to add linters and formatters to docker (#1486)

ftplugin/dockerfile.lua

@@ -1 +1 @@
-require("lsp").setup "docker"
+require("lsp").setup "dockerfile"

lua/config/defaults.lua

@@ -348,7 +348,7 @@ lvim.lang = {
       },
     },
   },
-  docker = {
+  dockerfile = {
     formatters = {},
     linters = {},
     lsp = {