Bump x509-limbo and/or wycheproof in CI (pyca#12821)

Co-authored-by: pyca-boringbot[bot] <pyca-boringbot[bot]+106132319@users.noreply.github.com>

Author: pyca-boringbot[bot]

.github/actions/fetch-vectors/action.yml

@@ -16,5 +16,5 @@ runs:
       with:
         repository: "C2SP/x509-limbo"
         path: "x509-limbo"
-        # Latest commit on the x509-limbo main branch, as of Apr 22, 2025.
-        ref: "7063e6eccef5aa9e4334bdda010380052f2abaa7" # x509-limbo-ref
+        # Latest commit on the x509-limbo main branch, as of Apr 29, 2025.
+        ref: "774892c271ea8d453d46c711726a359607c6a2cf" # x509-limbo-ref