Add retry to `docker push` in jenkins

[jvivian]

Last merged tool didn't make it onto quay due to a TLS handshake, despite the PR building fine.

DEBUG:__main__:hera/['make', 'push']: Put https://quay.io/v2/ucsc_cgl/hera/blobs/uploads/e845910e-03d3-4f48-aecb-13bbb6eb634a?digest=sha256%3Aa3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4: net/http: TLS handshake timeout

I'm guessing this is non-deterministic and adding retries if the tool fails (on this specific handshake error or just for all failed builds) would fix it.

[fnothaft]

+1