fix: lint errors.

Author: jainkuniya

app/src/main/java/com/zulip/android/activities/RecyclerMessageAdapter.java

@@ -458,7 +458,8 @@ public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, int vi
     }
 
     @Override
-    public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
+    public void onBindViewHolder(final RecyclerView.ViewHolder holder,  int pos) {
+        final int position = pos;
         switch (getItemViewType(position)) {
             case VIEWTYPE_MESSAGE_HEADER:
                 final MessageHeaderParent messageHeaderParent = (MessageHeaderParent) getItem(position);

app/src/main/java/com/zulip/android/models/MessageDateSeparator.java

@@ -3,6 +3,7 @@
 import com.zulip.android.util.DateMethods;
 
 import java.util.Date;
+import java.util.Locale;
 
 /**
  * Data Structure for message date separator
@@ -28,11 +29,11 @@ public Date getAboveMessageDate() {
 
     public String getLeftText() {
         String date = DateMethods.getStringDate(aboveMessageDate);
-        return date.isEmpty() ? "" : "\u25B2 " + date.toUpperCase();
+        return date.isEmpty() ? "" : "\u25B2 " + date.toUpperCase(Locale.US);
     }
 
     public String getRightText() {
         String date = DateMethods.getStringDate(belowMessageDate);
-        return date.isEmpty() ? "" : "\u25BC " + date.toUpperCase();
+        return date.isEmpty() ? "" : "\u25BC " + date.toUpperCase(Locale.US);
     }
 }