Interestingly, this patch would also help with Ruby 3.2 compatibility.
Ruby 3.2 removed `Kernel#=~`, so when misbehaving app return header
values in e.g. Integer
unicorn now choke on it:
app error: undefined method `=~' for 43747171631368:Integer (NoMethodError)
unicorn-6.1.0/lib/unicorn/http_response.rb:43:in `block in
http_response_write'
unicorn-6.1.0/lib/unicorn/http_response.rb:34:in `each'
unicorn-6.1.0/lib/unicorn/http_response.rb:34:in `http_response_write'
unicorn-6.1.0/lib/unicorn/http_server.rb:645:in `process_client'
Whereas on 3.1 and older, `42 =~ /\n/` would simply not match and cast
the header as a String.
