Automatically include short git SHA in each log trace

[KendallWeihe]

I'm not familiar with the logging DX with FTL, I'm just now ramping up, so apologies in advance for the incoherence.

In the past, for production debugging, it's been very valuable for each log trace to include the shortened git SHA for which the given code was built at. I've included the SHA as a prefix to a log trace, but if I understand correctly, we may automatically include it as an attribute -- again, not sure of the exact mechanism. When I've done this in the past, it's a build-time environment variable (for example setting an ENV in a Dockerfile) and then in the code at runtime it's read from the env var and included in the log trace.

I'm aware we have this logger:

logger := ftl.LoggerFromContext(ctx)

And I would imagine in our codebase I can make this feature request work, but I'm thinking it would be a good native feature for FTL. Meaning, if I instantiate the logger like I did above, then every log trace will automatically include the shortened git SHA for which the given code was built from.