Bump downstream dependencies in CI (#14186)

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

Author: pyca-boringbot[bot]

.github/workflows/ci.yml

@@ -468,8 +468,8 @@ jobs:
             PATH: scapy
           - DOWNSTREAM: sigstore-python
             REPO: sigstore/sigstore-python
-            # Latest commit on the sigstore-python main branch, as of Jan 20, 2026.
-            REF: 4ba9ca3d808b06b483e6ac241fe24f31f773202d
+            # Latest commit on the sigstore-python main branch, as of Jan 22, 2026.
+            REF: 802f96b1d86ed620bb27adf00c924bbc04833d69
             PATH: sigstore-python
     name: "Downstream tests for ${{ matrix.DOWNSTREAM }}"
     timeout-minutes: 15