Update Dockerfiles to Alpine 3.10

cargo/Dockerfile

@@ -1,6 +1,6 @@
 # Dockerfile for Azure/batch-shipyard (Cargo)
 
-FROM alpine:3.9
+FROM alpine:3.10
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>
 
 # copy in files

cascade/Dockerfile.docker

@@ -1,6 +1,6 @@
 # Dockerfile for Azure/batch-shipyard (Cascade/Docker)
 
-FROM alpine:3.9
+FROM alpine:3.10
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>
 
 # copy in files

cascade/Dockerfile.singularity

@@ -1,7 +1,7 @@
 # Dockerfile for Azure/batch-shipyard (Cascade/Singularity)
 
 # base image containing singularity
-FROM alfpark/singularity:3-default
+FROM alfpark/singularity:3.3.0-default
 
 FROM ubuntu:18.04
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>

federation/Dockerfile

@@ -1,6 +1,6 @@
 # Dockerfile for Azure/batch-shipyard (Federation)
 
-FROM alpine:3.9
+FROM alpine:3.10
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>
 
 # copy in files

heimdall/Dockerfile

@@ -1,6 +1,6 @@
 # Dockerfile for Azure/batch-shipyard (Heimdall)
 
-FROM alpine:3.9
+FROM alpine:3.10
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>
 
 # copy in files

slurm/Dockerfile

@@ -1,6 +1,6 @@
 # Dockerfile for Azure/batch-shipyard (Slurm)
 
-FROM alpine:3.9
+FROM alpine:3.10
 MAINTAINER Fred Park <https://github.com/Azure/batch-shipyard>
 
 # copy in files