Update @sebastic as a contributor

Author: snowman2

.all-contributorsrc

@@ -185,7 +185,8 @@
       "profile": "https://github.com/sebastic",
       "contributions": [
         "code",
-        "platform"
+        "platform",
+        "test"
       ]
     },
     {

README.md

@@ -55,7 +55,7 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
   </tr>
   <tr>
     <td align="center"><a href="https://github.com/heitorPB"><img src="https://avatars2.githubusercontent.com/u/13461702?v=4" width="100px;" alt="Heitor"/><br /><sub><b>Heitor</b></sub></a><br /><a href="https://github.com/pyproj4/pyproj/commits?author=heitorPB" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/sebastic"><img src="https://avatars3.githubusercontent.com/u/4605306?v=4" width="100px;" alt="Bas Couwenberg"/><br /><sub><b>Bas Couwenberg</b></sub></a><br /><a href="https://github.com/pyproj4/pyproj/commits?author=sebastic" title="Code">💻</a> <a href="#platform-sebastic" title="Packaging/porting to new platform">📦</a></td>
+    <td align="center"><a href="https://github.com/sebastic"><img src="https://avatars3.githubusercontent.com/u/4605306?v=4" width="100px;" alt="Bas Couwenberg"/><br /><sub><b>Bas Couwenberg</b></sub></a><br /><a href="https://github.com/pyproj4/pyproj/commits?author=sebastic" title="Code">💻</a> <a href="#platform-sebastic" title="Packaging/porting to new platform">📦</a> <a href="https://github.com/pyproj4/pyproj/commits?author=sebastic" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://github.com/nickeubank"><img src="https://avatars0.githubusercontent.com/u/9683693?v=4" width="100px;" alt="Nick Eubank"/><br /><sub><b>Nick Eubank</b></sub></a><br /><a href="https://github.com/pyproj4/pyproj/commits?author=nickeubank" title="Code">💻</a></td>
     <td align="center"><a href="https://www.math.uwaterloo.ca/~mdunphy/"><img src="https://avatars3.githubusercontent.com/u/9088426?v=4" width="100px;" alt="Michael Dunphy"/><br /><sub><b>Michael Dunphy</b></sub></a><br /><a href="https://github.com/pyproj4/pyproj/commits?author=mdunphy" title="Documentation">📖</a></td>
     <td align="center"><a href="http://matthew.dynevor.org"><img src="https://avatars2.githubusercontent.com/u/67612?v=4" width="100px;" alt="Matthew Brett"/><br /><sub><b>Matthew Brett</b></sub></a><br /><a href="#infra-matthew-brett" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a> <a href="#platform-matthew-brett" title="Packaging/porting to new platform">📦</a></td>