Update debian:bullseye-slim Docker digest to 257aa6a (#258)

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

Author: renovate[bot]

Dockerfile

@@ -8,7 +8,7 @@ RUN go mod download
 COPY ./ ./
 RUN go build
 
-FROM debian:bullseye-slim@sha256:52927eff8153b563244f98cdc802ba97918afcdf67f9e4867cbf1f7afb3d147b
+FROM debian:bullseye-slim@sha256:257aa6afc2edac932068b38032a00186a9a3d997ef8ac4bee742af161c140214
 WORKDIR /app
 
 RUN groupadd -g 1000 app && useradd -u 1000 -g app app