docs: add ahti123 as a contributor for code, bug (#578)

* 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

@@ -293,7 +293,8 @@
       "avatar_url": "https://avatars.githubusercontent.com/u/6291?v=4",
       "profile": "https://hyfen.net",
       "contributions": [
-        "doc", "code"
+        "doc",
+        "code"
       ]
     },
     {
@@ -304,6 +305,16 @@
       "contributions": [
         "bug"
       ]
+    },
+    {
+      "login": "ahti123",
+      "name": "Ahti Liin",
+      "avatar_url": "https://avatars.githubusercontent.com/u/22232632?v=4",
+      "profile": "https://github.com/ahti123",
+      "contributions": [
+        "code",
+        "bug"
+      ]
     }
   ],
   "contributorsPerLine": 7,