Bump haproxy version to 3.2.18

[CFN-CI]

Automatic bump from version 3.2.17 to version 3.2.18, downloaded from https://www.haproxy.org/download/3.2/src/haproxy-3.2.18.tar.gz.

After merge, consider releasing a new version of haproxy-boshrelease.

Changelog for HAProxy 3.2.18.

Please also check list of known open bugs for HAProxy 3.2.18.

The developer's summary for this release can be found in the Announcement post for the HAProxy 3.2.18 release.

HAPROXY CHANGELOG between 3.2.18 and 3.2.17

2026/05/06 : 3.2.18
    - BUG/MINOR: sink: do not free existing sinks on allocation error
    - BUG/MINOR: vars: make parse_store() return error on var_set() failure
    - BUG/MINOR: vars: don't store the variable twice with set-var-fmt
    - BUG/MINOR: vars: only print first invalid char in fill_desc()
    - BUG/MINOR: hpack: validate idx > 0 in hpack_valid_idx()
    - BUG/MEDIUM: cli: fix master CLI connection slot leak on client disconnect
    - BUG/MINOR: acl: fix a possible arg corruption in smp_fetch_acl_parse()
    - BUG/MINOR: map: do not leak a map descriptor on load error
    - CLEANUP: map/cli: fix some map-related help messages
    - BUG/MINOR: pattern: release the reference on failure to load from file
    - BUG/MEDIUM: mux-h2: fix the body_len to check when parsing request trailers
    - BUG/MAJOR: mux-h2: preset MSGF_BODY_CL on H2_SF_DATA_CLEN in h2c_dec_hdrs()
    - BUG/MINOR: dns: always validate the source address in responses
    - BUG/MINOR: tcpcheck: Properly report error for http health-checks
    - BUG/MINOR: resolvers: Free new requester on error when linking a resolution
    - BUG/MINOR: resolvers: Free opts on parse error in resolv_parse_do_resolve()
    - REGTESTS: add a regtest to validate various NTLM transitions
    - BUG/MEDIUM: mworker/cli: fix user and operator permission via @@<pid> in master CLI
    - BUG/MINOR: mworker/cli: check ci_insert() return value in pcli_parse_request()
    - DOC: acme: document missing acme-vars and provider-name keywords
    - REGTESTS: http-messaging: always send RFC8441 client settings to use ext connect
    - BUG/MINOR: h2: add decoding for :protocol in traces
    - BUG/MINOR: mux-h2: condition the processing of 8441 extension to global setting
    - MINOR: mux-h2: add a new message flag to indicate ext connect support
    - BUG/MINOR: h2: only accept :protocol with extended CONNECT
    - BUG/MINOR: acme: contact mail should be optional, don't pass ToS bool
    - BUG/MINOR: http-fetch: Fix http_auth_bearer() when custom header is used
    - BUG/MEDIUM: h1_htx: Remove reverved block on error during contig chunks parsing
    - BUG/MINOR: tools: read_line_to_trash() handle empty files without \n
    - BUG/MAJOR: http: forbid comma character in authority value
    - BUG/MEDIUM: h1: Enforce the authority validation during H1 request parsing

[peanball]

There are 2 reverts already in main that would apply to 3.2.18 and likely released with 3.2.19.

See https://www.haproxy.org/bugs/bugs-3.2.18.html

I would recommend to skip this version and go to 3.2.19.