Add missing translation of "to"

src/components/AppHeader.vue

@@ -38,7 +38,7 @@
           :disabled-dates="startDateDisabledDates"
           :title="$t('Select start date')"
         />
-        to
+        {{ $t("to") }}
         <Datepicker
           v-model="endDate"
           :use-utc="true"

src/locales/de.json

@@ -4,6 +4,7 @@
   "Layer settings": "Ebeneneinstellungen",
   "Show/hide layers": "Ebenen ein-/ausblenden",
   "Select start date": "Startdatum auswählen",
+  "to": "bis",
   "Select end date": "Enddatum auswählen",
   "Select user": "Benutzer auswählen",
   "Show all": "Alle anzeigen",

src/locales/en.json

@@ -4,6 +4,7 @@
   "Layer settings": "Layer settings",
   "Show/hide layers": "Show/hide layers",
   "Select start date": "Select start date",
+  "to": "to",
   "Select end date": "Select end date",
   "Select user": "Select user",
   "Show all": "Show all",