Add build status to readme

1 job for master in 101 minutes and 25 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test
failed #1020
build

01:41:25

 
Name Stage Failure
failed
build Test
==> Builds finished but no artifacts were created.
2020/02/12 04:00:54 /builds/community/openedx-configuration-ci/packer: plugin process exited
2020/02/12 04:00:54 [ERR] Error decoding response stream 7: EOF
2020/02/12 04:00:54 /builds/community/openedx-configuration-ci/packer: plugin process exited
2020/02/12 04:00:54 waiting for all plugin processes to complete...
2020/02/12 04:00:54 /builds/community/openedx-configuration-ci/packer: plugin process exited
2020/02/12 04:00:54 /builds/community/openedx-configuration-ci/packer: plugin process exited
make: *** [Makefile:17: build-digitalocean] Error 1
ERROR: Job failed: exit code 2