Bump net-protocol from 0.2.2 to 0.3.0

[dak2]

Problem

test (head, stdlib_test rubocop) fails on ruby-head with 8 errors, all in Net::HTTP / open-uri (run):

ArgumentError: wrong number of arguments (given 3, expected 1..2)
  net-protocol-0.2.2/lib/net/protocol.rb:194:in 'Net::BufferedIO#readuntil'
  ruby-head/lib/ruby/4.1.0+4/net/http/response.rb:164:in 'Net::HTTPResponse.read_line'

Cause

ruby/net-http#325 (in ruby/ruby as ruby/ruby@331568b2a) made Net::HTTPResponse use readuntil(limit:), which requires net-protocol >= 0.3.0.

ruby-head ships 0.3.0 as a default gem, so it is consistent on its own. But net/http is a default gem too, so its dependency never reaches Bundler's resolution — our lock pinned 0.2.2 through net-smtp, which carries no lower bound, and the installed 0.2.2 shadowed ruby-head's 0.3.0.

🤖 Generated with Claude Code

[ksss]

Thanks!