Fix typo in configuration.md DB_TYPE should be DB_CLIENT

[strefethen]

Describe the bug
In ./docs/configuration.md the Database section mentions setting DB_TYPE when it should be DB_CLIENT. The typo needs fixing.

To Reproduce

1. Open ./docs/configuration.md
2. Refer to the Database section
   // Note "DB_TYPE" which should read DB_CLIENT.

Additional context
Sorry for not creating a PR, before I can submit a PR I need approval from my employer and that process is working it's way through the system.

[larixer]

@strefethen Thank you, the approach with describing problem and solution in the Issue works great too! Fixed