docs: add salbalkus as a contributor for code (#454)

* docs: update README.md [skip ci]

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

---------

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

.all-contributorsrc

@@ -654,6 +654,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "salbalkus",
+      "name": "Salvador Balkus",
+      "avatar_url": "https://avatars.githubusercontent.com/u/45985925?v=4",
+      "profile": "https://salbalkus.github.io/",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -119,6 +119,7 @@ This project would not be possible without the contributions of:
     <tr>
       <td align="center" valign="top" width="14.28%"><a href="https://github.com/disberd"><img src="https://avatars.githubusercontent.com/u/12846528?v=4?s=100" width="100px;" alt="Alberto Mengali"/><br /><sub><b>Alberto Mengali</b></sub></a><br /><a href="https://github.com/JuliaEarth/GeoStats.jl/commits?author=disberd" title="Code">💻</a></td>
       <td align="center" valign="top" width="14.28%"><a href="https://www.math.uni-hamburg.de/en/home/lampert"><img src="https://avatars.githubusercontent.com/u/51029046?v=4?s=100" width="100px;" alt="Joshua Lampert"/><br /><sub><b>Joshua Lampert</b></sub></a><br /><a href="https://github.com/JuliaEarth/GeoStats.jl/commits?author=JoshuaLampert" title="Code">💻</a></td>
+      <td align="center" valign="top" width="14.28%"><a href="https://salbalkus.github.io/"><img src="https://avatars.githubusercontent.com/u/45985925?v=4?s=100" width="100px;" alt="Salvador Balkus"/><br /><sub><b>Salvador Balkus</b></sub></a><br /><a href="https://github.com/JuliaEarth/GeoStats.jl/commits?author=salbalkus" title="Code">💻</a></td>
     </tr>
   </tbody>
 </table>