fix: add support for kepub

issue: #301

src/converters/calibre.ts

@@ -39,6 +39,7 @@ export const properties = {
       "fb2",
       "html",
       "htmlz",
+      "kepub.epub",
       "lit",
       "lrf",
       "mobi",
@@ -65,7 +66,10 @@ export async function convert(
   options?: unknown,
 ): Promise<string> {
   return new Promise((resolve, reject) => {
-    execFile("ebook-convert", [filePath, targetPath], (error, stdout, stderr) => {
+    execFile(
+      "ebook-convert",
+      [filePath, targetPath],
+      (error, stdout, stderr) => {
         if (error) {
           reject(`error: ${error}`);
         }
@@ -79,6 +83,7 @@ export async function convert(
         }
 
         resolve("Done");
-    });
+      },
+    );
   });
 }