Pin Docker image alpine:edge

alpine:edge
->
alpine:edge@sha256:e64a0b2fc7ff870c2b22506009288daa5134da2b8c541440694b629fc22d792e

[atomist:generated]
[atomist-skill:atomist/docker-base-image-policy]

Author: atomist-bot

Dockerfile

@@ -16,7 +16,7 @@ RUN GOOS=linux GOARCH=amd64 go build -ldflags="-w -s" -o /transcoder main.go
 
 FROM vilsol/ffmpeg-alpine:latest@sha256:eb89de73d292f8b8fdffcba0f65caf13e3760300904a1192cd92d5b34e05ba05 as ffmpeg
 
-FROM alpine:edge
+FROM alpine:edge@sha256:e64a0b2fc7ff870c2b22506009288daa5134da2b8c541440694b629fc22d792e
 
 # ffmpeg
 COPY --from=ffmpeg /root/bin/ffmpeg /bin/ffmpeg