Move acorn dependency to devDependency, as it is already bundled in dist files, close #112

[Kocal]

Package size report
===================

Package info for "@symfony/[email protected]": 3.1 MB
  Released: 2025-01-09 07:16:42.242 +0000 UTC (2w5d ago)
  Downloads last week: 12,772 (21.82%)
  Estimated traffic last week: 40 GB
  Subdependencies: 17

Removed dependencies:
  - [email protected]: 547 kB (17.38%)
    Downloads last week: 22,267,720 (N/A% from 8.14.0)
    Downloads last week from "@symfony/[email protected]": 12,772 (N/A%)
    Traffic last week: N/A
    Traffic from "@symfony/[email protected]": 40 GB (N/A%)
    Subdependencies: 0 (0%)

Estimated new statistics:
  Package size: 3.1 MB → 2.4 MB (74.94%)
  Subdependencies: 17 → 16 (-1)
  Traffic with last week's downloads:
    For current version: 40 GB → 30 GB (10 GB saved)
    For all versions: 184 GB → 138 GB (46 GB saved)

A little disappointed, I thought it would save more bandwidth, but it's still worth it!