🐛 Signer.sign() is an async method so the typing should indicate it c…

…an be a promise

At the moment the typings are wrong because the sign function is reported to be `sign(pdfBuffer: Buffer) => Buffer`.
However, this is not a correct typing as the method is expected to return a promise as it is `async`. The sign method
can also return a Buffer (sync) as is done in the P12Signer. Therefore the typings should be
`sign(pdfBuffer: Buffer) => Promise<Buffer> | Buffer`.

packages/signer-p12/dist/P12Signer.d.ts

@@ -14,6 +14,11 @@ export class P12Signer extends Signer {
         asn1StrictParsing: boolean;
     };
     cert: any;
+    /**
+     * @param {Buffer} pdfBuffer
+     * @returns {Buffer}
+     */
+    sign(pdfBuffer: Buffer): Buffer;
 }
 export type SignerOptions = {
     passphrase?: string;

packages/utils/dist/Signer.d.ts

@@ -1,8 +1,8 @@
 export class Signer {
     /**
      * @param {Buffer} pdfBuffer
-     * @returns {Buffer}
+     * @returns {Promise<Buffer> | Buffer}
      */
-    sign(pdfBuffer: Buffer): Buffer;
+    sign(pdfBuffer: Buffer): Promise<Buffer> | Buffer;
 }
 //# sourceMappingURL=Signer.d.ts.map

packages/utils/dist/Signer.js

@@ -10,9 +10,9 @@ var _SignPdfError = require("./SignPdfError");
 class Signer {
   /**
    * @param {Buffer} pdfBuffer
-   * @returns {Buffer}
+   * @returns {Promise<Buffer> | Buffer}
    */
-  async sign(pdfBuffer) {
+  sign(pdfBuffer) {
     throw new _SignPdfError.SignPdfError(`sign() is not implemented on ${this.constructor.name}`, _SignPdfError.SignPdfError.TYPE_INPUT);
   }
 }

packages/utils/src/Signer.js

@@ -4,9 +4,9 @@ import {SignPdfError} from './SignPdfError';
 export class Signer {
     /**
      * @param {Buffer} pdfBuffer
-     * @returns {Buffer}
+     * @returns {Promise<Buffer> | Buffer}
      */
-    async sign(pdfBuffer) {
+    sign(pdfBuffer) {
         throw new SignPdfError(
             `sign() is not implemented on ${this.constructor.name}`,
             SignPdfError.TYPE_INPUT,