ci(integration): bump haybarn pin rc1 -> rc3 for blended named-args

The Integration suite has been red on main since the blended/LATERAL
table-in-out feature series landed. The only failing tests are
table_in_out/blended.test:133,139 (inline named args, `absolute := true`)
and table_in_out/lateral_batch.test:232 (batched correlated LATERAL) —
both pass against a locally-built extension from vgi main but fail against
the signed community extension pinned to haybarn-v1.5.4-rc1.

The vgi C++ commit that enables inline named args for blended functions
is titled "Haybarn rc3 binder patch", so the published extension carrying
that support ships with haybarn-v1.5.4-rc3 (the current Latest release).
Bump the pin so CI validates against the extension the fixtures require.

No product-code change; the perf work in the prior commit is unaffected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rustyconover

.github/workflows/integration.yml

@@ -32,7 +32,7 @@ env:
   VGI_REF: main
   # The Haybarn release providing the prebuilt haybarn-unittest binary. Must be
   # ABI-compatible with the community-published vgi extension.
-  HAYBARN_RELEASE: haybarn-v1.5.4-rc1
+  HAYBARN_RELEASE: haybarn-v1.5.4-rc3
 
 jobs:
   integration: