chore(deps): update google/cloud-sdk docker tag to v491 (#78)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Dockerfile

@@ -5,7 +5,7 @@ ARG WAITFOR_VERSION=2.2.4
 RUN curl -vsSLo /tmp/wait-for "https://github.com/eficode/wait-for/releases/download/v${WAITFOR_VERSION}/wait-for"
 RUN chmod +x /tmp/wait-for
 
-FROM google/cloud-sdk:490.0.0
+FROM google/cloud-sdk:491.0.0
 
 ENV PYTHONDONTWRITEBYTECODE=1
 ENV PYTHONUNBUFFERED=1