Update http4s-client, http4s-dsl to 0.21.0-M6 (#97)
Update http4s-client, http4s-dsl to 0.21.0-M6 (#97)

Co-authored-by: Sebastian Bruckner <afcdb580b77a08bb8840285b4bc18f219c6f58f5@users.noreply.github.com>

census-ecosystem/opencensus-scala