[v2.1.8] Adaptations from nghttp2 1.51.0
Changed
Since nghttp2 1.51.0, the nghttp2-asio library has been separated and percent_encode() has been
removed (new percent_encode_path exists, but do different job than needed).
Re-implement percent_encode function (#25).
Docker images
https://github.com/users/testillano/packages/container/package/http2comm
https://github.com/users/testillano/packages/container/package/http2comm_builder
Issues report
Re-implement percent_encode function (#25).