remove postgres nullls

after/plugin/null-ls.lua

@@ -1,12 +0,0 @@
-local null_ls = require("null-ls")
-
-null_ls.setup({
-  sources = {
-    -- sql lint
-    null_ls.builtins.diagnostics.sqlfluff.with({
-      extra_args = { "--dialect", "postgres" },   -- change to your dialect
-    }),
-    -- postgres format
-    null_ls.builtins.formatting.pg_format
-  },
-})