Update dependency rails to v8

Author: renovate[bot]

Gemfile

@@ -13,7 +13,7 @@ require File.join(Bundler::Plugin.index.load_paths("bundler-inject")[0], "bundle
 # Git. Remember to move these dependencies to your gemspec before releasing
 # your gem to rubygems.org.
 
-gem "rails", "~>7.2.3"
+gem "rails", "~>8.1.0"
 
 # security fixes for indirect dependencies
 gem "rack", ">=2.2.20" # CVE-2025-61919 https://github.com/advisories/GHSA-6xw4-3v39-52mm