We've been running against the dev branch of acme.sh since the initial
commit of the letsencrypt work -- at the time I feel like there were
things we needed that weren't in a release. Anyway, there is now an
issue causing ECC certificates to be made and failing to renew [1]
which we can't work-around.
Pin this to the current release. It would probably be good to pin
this to the "latest" release to avoid us forgetting to ever bump this
and ending up with even harder to debug bit-rot.
[1] https://github.com/acmesh-official/acme.sh/issues/4416
Change-Id: I0d07ba1b5ab77e07c67ad990e7bc78a9f90005a4
ecc2e9a69f