vim-patch:9.1.0266: filetype: earthfile files are not recognized (#28207)

Problem:  filetype: earthfile files are not recognized
Solution: Detect 'Earthfile' as earthfile
          (Gaëtan Lehmann)

closes: vim/vim#14408

28e5e7c484

Co-authored-by: Gaëtan Lehmann <gaetan.lehmann@gmail.com>

runtime/lua/vim/filetype.lua

@@ -1293,6 +1293,7 @@ local filename = {
   jbuild = 'dune',
   ['dune-workspace'] = 'dune',
   ['dune-project'] = 'dune',
+  Earthfile = 'earthfile',
   ['.editorconfig'] = 'editorconfig',
   ['elinks.conf'] = 'elinks',
   ['mix.lock'] = 'elixir',