Bump x509-limbo and/or wycheproof in CI (#14463)

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

Author: pyca-boringbot[bot]

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

@@ -9,8 +9,8 @@ runs:
       with:
         repository: "C2SP/wycheproof"
         path: "wycheproof"
-        # Latest commit on the wycheproof main branch, as of Mar 05, 2026.
-        ref: "d1b0cb0337202fa113b735b0e119f451af3c542d" # wycheproof-ref
+        # Latest commit on the wycheproof main branch, as of Mar 12, 2026.
+        ref: "78898104021ebd2cd98820e4112da89b1531d999" # wycheproof-ref
         persist-credentials: false
 
     - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2