Pin dependencies

Author: renovate[bot]

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:16-alpine AS build_node
+FROM node:16-alpine@sha256:a1f9d027912b58a7c75be7716c97cfbc6d3099f3a97ed84aa490be9dee20e787 AS build_node
 COPY frontend frontend
 WORKDIR frontend
 RUN npm install
@@ -12,7 +12,7 @@ COPY --from=build_node frontend/dist frontend/dist
 RUN go install ./cmd/${cmd}
 
 # Start fresh from a smaller image
-FROM alpine:3
+FROM alpine:3@sha256:56fa17d2a7e7f168a043a2712e63aed1f8543aeafdcee47c58dcffe38ed51099
 ARG cmd=ssl-status-board
 COPY --from=build_go /go/bin/${cmd} /app
 USER 1000