Fix reading config from file

[badsyntax]

Changes

This change fixes an error I'm experiencing when using secret files (instead of ENV vars) for config.

• Here's a related discussion: Error parsing BASE_URL: no function clause matching in URI.parse/1 #1311
• Here's where I discovered a potential fix: Passing secrets as environment variables #1105 (comment)

Tests

• Automated tests have been added
• This PR does not require tests

Changelog

• Entry has been added to changelog
• This PR does not make a user-facing change

Documentation

• Docs have been updated
• This change does not need a documentation update

[ukutaht]

Looks good to me.

@happysalada are you not using file-based config option? I'm surprised it hasn't been working the whole time

[badsyntax]

Thanks for the quick merge! I've verified the fix using plausible/analytics:master.

[happysalada]

I am actually waiting for a systemd update to enable load credential. (the equivalent of docker secrets for systemd)
originally I thought that update was coming fast, but it still hasn't landed.
My bad for not testing directly.
@badsyntax thanks for fixing this!

[ukutaht]

All good, thanks!