Drop git usage from gemspec

Forwarded: not-needed

--- a/ffaker.gemspec
+++ b/ffaker.gemspec
@@ -26,11 +26,7 @@
   s.rdoc_options = ['--charset=UTF-8']
   s.extra_rdoc_files = %w[README.md LICENSE Changelog.md]
 
-  s.files = `git ls-files`
-            .split("\n")
-            .sort
-            .grep_v(/^\./)
-            .grep_v(/^(rdoc|pkg)/)
+  s.files = Dir.glob("**/*").select {|v| v !~ /^(debian|rdoc|pkg)/}
 
   s.metadata = {
     'changelog_uri' => 'https://github.com/ffaker/ffaker/blob/main/Changelog.md',