nghttp3 v1.17.0

What's Changed

• lib: Add nghttp3_downcase_byte by @tatsuhiro-t in #518
• lib: Fix header name validation by @tatsuhiro-t in #519
• lib: Reformat downcase table by @tatsuhiro-t in #520
• Add nghttp3_conn_stream_flushed by @tatsuhiro-t in #521
• lib: Take into account non-DATA frame in nghttp3_conn_is_stream_flushed by @tatsuhiro-t in #522
• Update scripts by @tatsuhiro-t in #523
• Reformat huffman data tables by @tatsuhiro-t in #524
• Update doc by @tatsuhiro-t in #525
• lib: Treat non-existent stream flushed by @tatsuhiro-t in #526
• Bump sfparse by @tatsuhiro-t in #527
• lib: Add the public API to encode and decode variable-length integer by @tatsuhiro-t in #529
• build(deps): bump actions/checkout from 6 to 7 by @dependabot[bot] in #530
• Add missing version-added by @tatsuhiro-t in #531

Full Changelog: v1.16.0...v1.17.0