Lock net-protocol version to match the monkey patch

What does this MR do and why?

Ruby extracted net-protocol (and some other net-* related functionality) into separate gems. GitLab has BufferedIO patch that may rely on a different version of the gem/functionality. Let's lock the version and use 0.1.x version, the one that contains the current BufferedIO patch implementation:

• net-protocol implementation: https://github.com/ruby/net-protocol/blob/v0.1.3/lib/net/protocol.rb#L190
• Patch implementation: https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/buffered_io.rb#L25

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Some more context: Rails 7 now explicitly adds net-imap, net-pop, net-smtp along with net-protocol and since the version is not locked, the newest one (0.2.1) is included with different BufferedIO implementation.

It seems that Ruby has a different version of net/protocol implementation

• Ruby 3.2.1 => net-protocol 0.2.1: https://github.com/ruby/ruby/blob/v3_2_1/lib/net/protocol.rb
• Ruby 3.1.3 => net-protocol 0.1.2: https://github.com/ruby/ruby/blob/v3_1_3/lib/net/protocol.rb

Locking the gem version to 0.1.x will allow us to postpone patching the new version of the method until we upgrade to Ruby 3.1.3