Bump x509-limbo and/or wycheproof in CI (#12951)

Co-authored-by: pyca-boringbot[bot] <pyca-boringbot[bot][email protected]>

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 May 13, 2025.
-        ref: "44b61a40371d90b50c4310464ad0e45c8ba08331" # x509-limbo-ref
+        # Latest commit on the x509-limbo main branch, as of May 20, 2025.
+        ref: "742702ed5930065aafc461c0232802c6a0d1e992" # x509-limbo-ref