Update btcpay-server to version 2.0.8

[al-lac]

Tested on Umbrel Home, maybe you can also take a look @nmfretz @sharknoon.

[github-actions[bot]]

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Linting Results

Severity	File	Description
ℹ️	btcpay-server/docker-compose.yml	Potentially using unsafe user in service "postgres": The default container user "root" can lead to security vulnerabilities. If you are using the root user, please try to specify a different user (e.g. "1000:1000") in the compose file or try to set the UID/PUID and GID/PGID environment variables to 1000.

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Symbol	Description
❌	Error: This must be resolved before this PR can be merged.
⚠️	Warning: This is highly encouraged to be resolved, but is not strictly mandatory.
ℹ️	Info: This is just for your information.

[sharknoon]

I have installed the live version of btcpay-server, set it up and then updated to app to this new version (2.0.8). It has kept the data and it works fine for me. But I haven't intensively tested the app because I am not that familiar with crypto payment providers.

[nmfretz]

Reviewed and tested. Working great @al-lac, we're good to go live.