Bump downstream dependencies in CI (#14762)

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

Author: pyca-boringbot[bot]

.github/workflows/ci.yml

@@ -426,8 +426,8 @@ jobs:
             PATH: pyopenssl
           - DOWNSTREAM: twisted
             REPO: twisted/twisted
-            # Latest commit on the twisted trunk branch, as of Apr 25, 2026.
-            REF: 33f30805ff840a3a70758d25cacbd7e474bce0c2
+            # Latest commit on the twisted trunk branch, as of Apr 28, 2026.
+            REF: b71fe03b9cdb422457dda2b6823dd25126ba988e
             PATH: twisted
           - DOWNSTREAM: aws-encryption-sdk-python
             REPO: awslabs/aws-encryption-sdk-python
@@ -436,8 +436,8 @@ jobs:
             PATH: aws-encryption-sdk-python
           - DOWNSTREAM: aws-dynamodb-encryption-python
             REPO: awslabs/aws-dynamodb-encryption-python
-            # Latest commit on the aws-dynamodb-encryption-python master branch, as of Jan 29, 2026.
-            REF: ff8ceec703f6e85cac3a3d658f3de06226cabdf4
+            # Latest commit on the aws-dynamodb-encryption-python master branch, as of Apr 28, 2026.
+            REF: 09e274019bde989c2cdf8af025a9a4bcc11b8426
             PATH: aws-dynamodb-encryption-python
           - DOWNSTREAM: certbot
             REPO: certbot/certbot
@@ -456,13 +456,13 @@ jobs:
             PATH: mitmproxy
           - DOWNSTREAM: scapy
             REPO: secdev/scapy
-            # Latest commit on the scapy master branch, as of Apr 24, 2026.
-            REF: 1745d390da0bee6e7c83270723f729c441999d00
+            # Latest commit on the scapy master branch, as of Apr 28, 2026.
+            REF: bfab325b4a7c2ab8d26a042ef55aeeb845d3f1cc
             PATH: scapy
           - DOWNSTREAM: sigstore-python
             REPO: sigstore/sigstore-python
-            # Latest commit on the sigstore-python main branch, as of Apr 27, 2026.
-            REF: 39bef2d609e16b818368b750d5aa62b937c852d9
+            # Latest commit on the sigstore-python main branch, as of Apr 28, 2026.
+            REF: 39e34dac3ead9d82258576eddd0760067de99999
             PATH: sigstore-python
     name: "Downstream tests for ${{ matrix.DOWNSTREAM }}"
     timeout-minutes: 15