If `link-commits-to-pull-request` is true, verify Azure DevOps Org and PAT are set

[joshjohanning]

Verify that both are not empty

if ${{ inputs.link-commits-to-pull-request }}; then
  # make the call to main.js to do the linking
  # TODO: check to see if org/pat are set
  echo "Attempting to link work item ${WORKITEM} to pull request ${PULL_NUMBER}..."
  REPO_TOKEN=${{ inputs.github-token }} AZURE_DEVOPS_ORG=${{ inputs.azure-devops-organization }} AZURE_DEVOPS_PAT=${{ inputs.azure-devops-token }} WORKITEMID=$WORKITEM PULLREQUESTID=${{ github.event.number }} REPO=${{ github.repository }} node $main
  echo "...PR linked to work item"
fi