This supplements the release process. We inject Github metadata into two
version.json files; the 'version' value will depend on the type of event,
for release tag events it should be the same as the release tag (i.e. the
app version). This should make version information available to the /config
endpoint on any push, and the frontend should display the backend version.
(For extra safety we will also want to get the frontend version and display
that, but this commit only supplies the barest necessities.)
So that E2E tests in Github Actions can connect to Dimail container.
Previously we were attempting to connect as if from the outside. But
the E2E process is in fact inside the Docker Compose network.
("The tests came from inside the house !")
https://tvtropes.org/pmwiki/pmwiki.php/Main/TheCallsAreComingFromInsideTheHouse
Adapt domain creationg request to latest protocol version, also
make error reporting more robust: don't assume utf-8 but use the
response's encoding, don't assume the error is JSON (it won't be
when getting a 500) but reproduce the whole thing instead.
Start the Dimail container (in CI and local testing) when starting
the app. The pull_policy should have no effect on CI (because it starts
from a blank slate) but ensure we test against the most recent version
of the chosen tag.
