RateMeDialog: Don't show again after rating

We can't really know if the user really rated, but at
least this PR will make Juergen happy.

For #38

Author: guruz

opencloudApp/src/main/java/eu/opencloud/android/ui/dialog/RateMeDialog.java

@@ -104,6 +104,11 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle sa
             } catch (ActivityNotFoundException e) {
                 ActivityExtKt.goToUrl(requireActivity(), PLAY_STORE_URI + packageName, null);
             }
+            SharedPreferences preferences = getActivity().getSharedPreferences
+                    (AppRater.APP_RATER_PREF_TITLE, 0);
+            SharedPreferences.Editor editor = preferences.edit();
+            editor.putBoolean(AppRater.APP_RATER_PREF_DONT_SHOW, true);
+            editor.apply();
             dialog.dismiss();
         });