Correct year length validation

templates/components/date_picker.html

@@ -50,7 +50,7 @@
           <label>Year</label>
           <input
             id="date-year"
-            maxlength="2"
+            maxlength="4"
             type="number"
             v-model="year"
             {% if maxdate %}max="{{ maxdate.year }}"{% endif %}