fix: Modified the DSL.jsonEntry (closes #7)

Previously the jsonEntry was
```
is ColumnField -> {
    DSL.jsonEntry(
             alias,
             DSL.field(DSL.name(field.name))
    )
}
```

Modified that so that, the issue of aliasing is resolved
```
is ColumnField -> {
    DSL.jsonEntry(
             alias,
             DSL.field(DSL.name(alias))
    )
}
```

ndc-connector-mysql/src/main/kotlin/io/hasura/mysql/JSONGenerator.kt

@@ -56,7 +56,7 @@ object JsonQueryGenerator : BaseQueryGenerator() {
                                         is ColumnField -> {
                                             DSL.jsonEntry(
                                                 alias,
-                                                DSL.field(DSL.name(field.column))
+                                                DSL.field(DSL.name(alias))
                                             )
                                         }