Pin Docker image mcr.microsoft.com/dotnet/sdk:6.0

--platform=$BUILDPLATFORM
->
mcr.microsoft.com/dotnet/sdk:6.0@sha256:2fdad630a59fbdecbfcc6aaf3ccae96eea0e8d24cd4607669fde0de107a94c53

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

Signed-off-by: Atomist Bot <bot@atomist.com>

nginx-aspnet-mysql/backend/Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1.4
 
-FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:6.0 AS base
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:6.0@sha256:2fdad630a59fbdecbfcc6aaf3ccae96eea0e8d24cd4607669fde0de107a94c53 AS base
 
 WORKDIR /src