Replace File.exists? with File.exist? for Ruby 3.2 compatibility

Author: tuxmea

templates/server/post-receive.erb

@@ -100,7 +100,7 @@ $stdin.each_line do |line|
       Dir.chdir environment_path
       do_cmd("git fetch --all")
       do_cmd("git reset --hard 'origin/#{branchname}'")
-      if File.exists? "#{environment_path}/.gitmodules"
+      if File.exist? "#{environment_path}/.gitmodules"
         # ensure that we remove deleted sub modules too
         do_cmd("git status --short").split("\n").each do |file|
           # ?? old_submodule/