fix(types): relax index signature in JSONPgSmartTags

[LeoBakerHytch]

Just a tiny PR so that instead of this:

export const TagsPlugin = makeJSONPgSmartTagsPlugin({
    version: 1,
    config: {
        class: {
            foo: {
                tags: {
                    omit: 'all',
                },
            },
        },
        attribute: {},
        procedure: {},
        constraint: {},
    },
});

I can write this:

export const TagsPlugin = makeJSONPgSmartTagsPlugin({
    version: 1,
    config: {
        class: {
            foo: {
                tags: {
                    omit: 'all',
                },
            },
        },
    },
});