fix(config): a DB URL error 'does not validate as url' #705

[kotakanbe]

What did you implement:

Remove URL validation of go-cve-dict, oval-dict, gost DB URL in config.toml

Fixes #705

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.

Checklist:

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• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
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• Pass the test by make test
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• Update the messages below

Is this ready for review?: YES