Restore valid base image version (#442)

Author: Ryan Shaffer

Build/images/samples/Dockerfile

@@ -2,7 +2,7 @@
 # https://github.com/microsoft/iqsharp/blob/main/images/iqsharp-base/Dockerfile.
 # As per Binder documentation, we choose to use an SHA sum here instead of a
 # tag.
-FROM mcr.microsoft.com/quantum/iqsharp-base:0.13.201118141-beta
+FROM mcr.microsoft.com/quantum/iqsharp-base:0.13.20102604
 
 # Mark that this Dockerfile is used with the samples repository.
 ENV IQSHARP_HOSTING_ENV=SAMPLES_DOCKERFILE