CI: Retry codecov uploads three times
CI: Retry codecov uploads three times

Sometimes codecov uploads fail:

$ bash <(curl -s https://codecov.io/bash)
curl: (7) Failed to connect to codecov.io port 443: Connection timed
out

travis_retry is a function provided by Travis-CI that will attempt to
run a command up to 3 times if it exits with a non-zero exit code

pion/dtls