chore(dockerhub): Add dockerhub credentials

Author: bkochendorfer

buildspec.yml

@@ -4,6 +4,7 @@ phases:
   install:
     commands:
       - ". ci/install_deps.sh"
+      -  echo "${DOCKERHUB_PASSWORD}" | docker login -u "${DOCKERHUB_USERNAME}" --password-stdin 
   pre_build:
     commands:
       - export COMMIT_SHA=$CODEBUILD_RESOLVED_SOURCE_VERSION
@@ -26,4 +27,4 @@ phases:
       - if [ "$PR" = "" ]; then ./do.sh deploy; fi
 cache:
   paths:
-    - $HOME/.cargo
+    - $HOME/.cargo