chore(deps): pin dependencies (#844)

Co-authored-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

Dockerfile

@@ -3,7 +3,7 @@
 #        -> Why static linking? We want to ensure we can switch base-image with little to no effort.
 #   2. It builds a running environment. This is the environment that exists for the Go binary, and should have all necessary pieces to run the application.
 
-FROM golang:1.25.3-alpine AS app
+FROM golang:1.25.3-alpine@sha256:aee43c3ccbf24fdffb7295693b6e33b21e01baec1b2a55acc351fde345e9ec34 AS app
 
 RUN apk add --no-cache git
 
@@ -16,7 +16,7 @@ RUN --mount=type=cache,target=/go/pkg/mod CGO_ENABLED=0 go build \
   -ldflags '-s -w -extldflags "-static"' \
   .
 
-FROM debian:13 AS output_image
+FROM debian:13@sha256:72547dd722cd005a8c2aa2079af9ca0ee93aad8e589689135feaed60b0a8c08d AS output_image
 
 LABEL maintainer="Grafana team <[email protected]>"
 LABEL org.opencontainers.image.source="https://github.com/grafana/grafana-image-renderer/tree/master/go.Dockerfile"