deps: update http-parser to 2.6.0

@nodejs/tsc @nodejs/http

significant updates:

• [777ba4eded] - src: introduce http_parser_url_init (Fedor Indutny) nodejs/http-parser#225
• [e557b62744] - src: support LINK/UNLINK (RFC 2068, draft-snell-link-method) (Olivier Mengué) nodejs/http-parser#267
• [eb5e9928b4] - src: support ACL (WebDAV, RFC3744, Section 8.1). (Ivan Enderlin) joyent/http-parser#260
• [8b1d652322] - src: support BIND/REBIND/UNBIND (WebDAV, RFC5842) (Ivan Enderlin) joyent/http-parser#242
• [7d75dd7325] - src: support IPv6 Zone ID as per RFC 6874 (Tatsuhiro Tsujikawa) joyent/http-parser#253

Full changelog (since v2.5.0):

• [39c2c1e573] - Bump version to 2.5.0 (Fedor Indutny)
• [483eca7989] - doc: updated README.md to include multi-threading example (Lucas Berezy) nodejs/http-parser#256
• [b36c2a9ece] - header: treat Wine like MinGW (Andrew Udvare) joyent/http-parser#259
• [2896229a13] - make: fix dynamic library extension for OS X (Guo Xiao)
• [4f69be2221] - readme: update WebSocket link to RFC6455 (Ivan Enderlin) joyent/http-parser#240
• [777ba4eded] - (SEMVER-MINOR) src: introduce http_parser_url_init (Fedor Indutny) nodejs/http-parser#225
• [e557b62744] - (SEMVER-MINOR) src: support LINK/UNLINK (RFC 2068, draft-snell-link-method) (Olivier Mengué) nodejs/http-parser#267
• [e01811e7f4] - src: fixed compile error C2143 for vs2012 (Sebastian Philipp) joyent/http-parser#261
• [eb5e9928b4] - (SEMVER-MINOR) src: support ACL (WebDAV, RFC3744, Section 8.1). (Ivan Enderlin) joyent/http-parser#260
• [8b1d652322] - (SEMVER-MINOR) src: support BIND/REBIND/UNBIND (WebDAV, RFC5842) (Ivan Enderlin) joyent/http-parser#242
• [7d75dd7325] - (SEMVER-MINOR) src: support IPv6 Zone ID as per RFC 6874 (Tatsuhiro Tsujikawa) joyent/http-parser#253
• [ab0b162ef6] - src: use ARRAY_SIZE instead of sizeof() (dlmeetei@gmail.com) joyent/http-parser#252
• [39ff0975c2] - src: remove double check (Jan Schär) joyent/http-parser#248
• [f6f436a12e] - src: fix invalid memory access in http_parse_host (Daniel Knoppel (Phusion)) joyent/http-parser#246
• [b5bcca8f92] - test: SEARCH, PURGE and MKCALENDAR (Ivan Enderlin) joyent/http-parser#241