docs: add gonzalobarbaran as a contributor for code (#445)

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

.all-contributorsrc

@@ -550,6 +550,15 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "gonzalobarbaran",
+      "name": "gonzalobarbaran",
+      "avatar_url": "https://avatars.githubusercontent.com/u/59395855?v=4",
+      "profile": "https://github.com/gonzalobarbaran",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -170,6 +170,7 @@ This library could only exist thanks to the dedication of many volunteers around
     <td align="center"><a href="https://github.com/cgkoutzigiannis"><img src="https://avatars.githubusercontent.com/u/41803093?v=4?s=100" width="100px;" alt=""/><br /><sub><b>cgkoutzigiannis</b></sub></a><br /><a href="https://github.com/PyFPDF/fpdf2/commits?author=cgkoutzigiannis" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/iwayankurniawan"><img src="https://avatars.githubusercontent.com/u/30134645?v=4?s=100" width="100px;" alt=""/><br /><sub><b>I Wayan Kurniawan</b></sub></a><br /><a href="https://github.com/PyFPDF/fpdf2/commits?author=iwayankurniawan" title="Documentation">📖</a></td>
     <td align="center"><a href="https://rysta.io"><img src="https://avatars.githubusercontent.com/u/4029642?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sven Eliasson</b></sub></a><br /><a href="https://github.com/PyFPDF/fpdf2/commits?author=comino" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/gonzalobarbaran"><img src="https://avatars.githubusercontent.com/u/59395855?v=4?s=100" width="100px;" alt=""/><br /><sub><b>gonzalobarbaran</b></sub></a><br /><a href="https://github.com/PyFPDF/fpdf2/commits?author=gonzalobarbaran" title="Code">💻</a></td>
   </tr>
 </table>