Fix for the latest neovim

autoload/health/defx.vim

@@ -6,15 +6,15 @@
 
 function! s:check_required_python_for_defx() abort
   if has('python3')
-    call health#report_ok('has("python3") was successful')
+    call s:report_ok('has("python3") was successful')
   else
-    call health#report_error('has("python3") was not successful')
+    call s:report_error('has("python3") was not successful')
   endif
 
   if defx#init#_python_version_check()
-    call health#report_error('Python 3.6.1+ was successful')
+    call s:report_error('Python 3.6.1+ was successful')
   else
-    call health#report_ok('Python 3.6.1+ was successful')
+    call s:report_ok('Python 3.6.1+ was successful')
   endif
 endfunction
 
@@ -23,3 +23,19 @@ function! health#defx#check() abort
 
   call s:check_required_python_for_defx()
 endfunction
+
+function! s:report_ok(report) abort
+  if has('nvim-0.10')
+    call v:lua.vim.health.ok(a:report)
+  else
+    call health#report_ok(a:report)
+  endif
+endfunction
+
+function! s:report_error(report) abort
+  if has('nvim-0.10')
+    call v:lua.vim.health.error(a:report)
+  else
+    call health#report_error(a:report)
+  endif
+endfunction