www/gitlab-ce: Fixed problem with asset compilation

The old autoprefixer gem used by gitlab cause at the upgrade the
following error message (cause by newer execjs gem):
Done in 0.68s.
rake aborted!
ExecJS::ProgramError: TypeError: Cannot read property 'version' of undefined
eval (eval at <anonymous> ((execjs):1:213), <anonymous>:1:10)
(execjs):1:213
(execjs):19:14
(execjs):1:40
Object.<anonymous> ((execjs):1:58)
Module._compile (node:internal/modules/cjs/loader:1109:14)
Object.Module._extensions..js (node:internal/modules/cjs/loader:1138:10)
Module.load (node:internal/modules/cjs/loader:989:32)
Function.Module._load (node:internal/modules/cjs/loader:829:14)
Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:76:12)
/usr/local/www/gitlab-ce/lib/gitlab/task_helpers.rb:18:in `invoke_and_time_task'
/usr/local/www/gitlab-ce/lib/tasks/gitlab/assets.rake:59:in `each'
/usr/local/www/gitlab-ce/lib/tasks/gitlab/assets.rake:59:in `block (3 levels) in <top (required)>'
/usr/local/bin/bundle:23:in `load'
/usr/local/bin/bundle:23:in `<main>'
Tasks: TOP => assets:precompile
(See full trace by running task with --trace)