[Bug]: Remove typescript files from build

[what1s1ove]

Because the package is published together with TypeScript files (which is bad practice), various errors occur depending on the build tool.

For example, the problem in this issue https://github.com/ryu1kn/csv-writer/issues/92. Another example is when I want to enable the exactOptionalPropertyTypes option in the TypeScript config, it complains about the use of TS files in the node_modules folder, which we cannot fix.

node_modules/csv-writer/src/lib/csv-writer-factory.ts:30:85 - error TS2379: Argument of type '{ header: string[] | undefined; fieldDelimiter: string | undefined; recordDelimiter: string | undefined; alwaysQuote: boolean | undefined; }' is not assignable to parameter of type 'ArrayCsvStringifierParams' with 'exactOptionalPropertyTypes: true'. Consider adding 'undefined' to the types of the target's properties.
  Types of property 'header' are incompatible.
    Type 'string[] | undefined' is not assignable to type 'string[]'.
      Type 'undefined' is not assignable to type 'string[]'.

 30         const csvStringifier = this.csvStringifierFactory.createArrayCsvStringifier({
                                                                                        ~
 31             header: params.header,
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
... 
 34             alwaysQuote: params.alwaysQuote
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 35         });
    ~~~~~~~~~

Please consider publishing the package with only JS files, along with type declarations (d.ts files).