fixing yarnpkg error

provider/legal-aws/build-aws/buildspec.yaml

@@ -44,6 +44,9 @@ phases:
       - $(aws ecr get-login --no-include-email --region $AWS_REGION) # authenticate with ECR via the AWS CLI
   build:
     commands:
+      # fix error noted here: https://github.com/yarnpkg/yarn/issues/7866
+      - curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+      
       - export REPO_NAME=${PWD##*/}
       - export OUTPUT_DIR="dist"
       - export BRANCH_NAME=`echo ${CODEBUILD_SOURCE_VERSION} | awk '{gsub("refs/heads/","");gsub("\\.","-");gsub("[[:space:]]","-")}1' | sed 's/\//-/g' | awk '{print tolower($0)}'`