Bump third_party/libwebsockets/repo from `18fdb0d` to `a1cbc02` (#29906)

Bumps [third_party/libwebsockets/repo](https://github.com/warmcat/libwebsockets) from `18fdb0d` to `a1cbc02`.
- [Commits](https://github.com/warmcat/libwebsockets/compare/18fdb0d6ecfd7ec8090ed7164fd6e4895a89e12b...a1cbc02aeb28303a22781f3a37730fefbf2d6fce)

---
updated-dependencies:
- dependency-name: third_party/libwebsockets/repo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/libwebsockets/repo b/third_party/libwebsockets/repo
index 18fdb0d..a1cbc02 160000
--- a/third_party/libwebsockets/repo
+++ b/third_party/libwebsockets/repo
@@ -1 +1 @@
-Subproject commit 18fdb0d6ecfd7ec8090ed7164fd6e4895a89e12b
+Subproject commit a1cbc02aeb28303a22781f3a37730fefbf2d6fce