Rename dynamodb DOWNSTREAM to aws-dynamodb-encryption-python (#14214)

This fixes the downstream bump script's comment_pattern not matching,
which caused the date in the comment not to be updated on bumps.

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: alex

…/downstream.d/dynamodb-encryption-sdk.sh …ream.d/aws-dynamodb-encryption-python.sh.github/downstream.d/dynamodb-encryption-sdk.sh renamed to .github/downstream.d/aws-dynamodb-encryption-python.sh .github/downstream.d/dynamodb-encryption-sdk.sh renamed to .github/downstream.d/aws-dynamodb-encryption-python.sh

@@ -441,7 +441,7 @@ jobs:
             # Latest commit on the aws-encryption-sdk-python master branch, as of Jan 27, 2026.
             REF: b441d84460e7bb9ffff67e7fe52ccd0f857c5b86
             PATH: aws-encryption-sdk-python
-          - DOWNSTREAM: dynamodb-encryption-sdk
+          - DOWNSTREAM: aws-dynamodb-encryption-python
             REPO: awslabs/aws-dynamodb-encryption-python
             # Latest commit on the aws-dynamodb-encryption-python master branch, as of Aug 05, 2025.
             REF: c488328ffdc9afcc6f8d46390b79cfdd650d7fed