Migrating from Gun 2.3 to 2.4

Gun 2.4 fixes a number of security vulnerabilities. It also has a few new options.

Gun 2.4 updates Cowlib to 2.17.0. Both applications must be updated as they both contain security fixes.

Gun 2.4 requires Erlang/OTP 24.0 or greater.

Features added

• Add invalid_request_headers request option. This option is enabled by default and adds a check that raises an exception when invalid headers are detected when asking Gun to send requests.
• Add max_header_block_size and max_trailer_block_size HTTP/1.1 options.
• Update Cowlib to 2.17.0.

Bugs fixed

• Reject HTTP/1.1 101 responses when no upgrade was requested with a protocol_error connection error.
• Restrict push promises to the original request's authority.
• Fix keepalive_tolerance with unrequested pings.