docs: add shapiromh as a contributor for code (#907)

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

---------

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

Author: allcontributors[bot]

.all-contributorsrc

@@ -324,6 +324,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "shapiromh",
+      "name": "Matt Shapiro",
+      "avatar_url": "https://avatars.githubusercontent.com/u/2327833?v=4",
+      "profile": "http://shapiromh.com",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 8,

README.md

@@ -281,6 +281,7 @@ Thanks goes to these wonderful people:
     <tr>
       <td align="center" valign="top" width="12.5%"><a href="https://github.com/jestover"><img src="https://avatars.githubusercontent.com/u/11298484?v=4?s=100" width="100px;" alt="Joseph Stover"/><br /><sub><b>Joseph Stover</b></sub></a><br /><a href="https://github.com/py-econometrics/pyfixest/commits?author=jestover" title="Documentation">📖</a></td>
       <td align="center" valign="top" width="12.5%"><a href="https://github.com/JaapCTJ"><img src="https://avatars.githubusercontent.com/u/157970664?v=4?s=100" width="100px;" alt="JaapCTJ"/><br /><sub><b>JaapCTJ</b></sub></a><br /><a href="https://github.com/py-econometrics/pyfixest/commits?author=JaapCTJ" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://shapiromh.com"><img src="https://avatars.githubusercontent.com/u/2327833?v=4?s=100" width="100px;" alt="Matt Shapiro"/><br /><sub><b>Matt Shapiro</b></sub></a><br /><a href="https://github.com/py-econometrics/pyfixest/commits?author=shapiromh" title="Code">💻</a></td>
     </tr>
   </tbody>
 </table>