docs: add christofferh as a contributor (#1400)

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]
Co-authored-by: Nallcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
Co-authored-by: NIlkka Seppälä <ilkka.seppala@gofore.com>

.all-contributorsrc

@@ -291,6 +291,15 @@
         "code"
       ]
     },
+    {
+      "login": "christofferh",
+      "name": "Christoffer Hamberg",
+      "avatar_url": "https://avatars1.githubusercontent.com/u/767643?v=4",
+      "profile": "https://christofferh.com",
+      "contributions": [
+        "code"
+      ]
+    },
     {
       "login": "dgruntz",
       "name": "Dominik Gruntz",

README.md

@@ -150,6 +150,7 @@ This project is licensed under the terms of the MIT license.
     <td align="center"><a href="https://github.com/leogtzr"><img src="https://avatars0.githubusercontent.com/u/1211969?v=4" width="100px;" alt=""/><br /><sub><b>Leo Gutiérrez Ramírez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=leogtzr" title="Code">💻</a></td>
     <td align="center"><a href="https://bitbucket.org/hannespernpeintner/"><img src="https://avatars3.githubusercontent.com/u/1679437?v=4" width="100px;" alt=""/><br /><sub><b>Hannes</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hannespernpeintner" title="Code">💻</a></td>
     <td align="center"><a href="https://github.com/dgruntz"><img src="https://avatars0.githubusercontent.com/u/1516800?v=4" width="100px;" alt=""/><br /><sub><b>Dominik Gruntz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dgruntz" title="Code">💻</a></td>
+    <td align="center"><a href="https://christofferh.com"><img src="https://avatars1.githubusercontent.com/u/767643?v=4" width="100px;" alt=""/><br /><sub><b>Christoffer Hamberg</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=christofferh" title="Code">💻</a></td>
   </tr>
 </table>