add serialVersionUID to Attendee and Meeting Classes to fix incompatibilities between ZoomHelper versions

app/src/main/java/de/joel/zoomhelper/MainActivity.java

@@ -843,6 +843,7 @@ public class MainActivity extends AppCompatActivity {
 
 
 class Attendee implements Serializable {
+    private static final long serialVersionUID = 6196688086302483907L;
     public String name;
     public String num;
 
@@ -853,6 +854,7 @@ class Attendee implements Serializable {
 }
 
 class Meeting implements Serializable {
+    private static final long serialVersionUID = 2606722401897866931L;
     public String meetingName;
     public String meetingID;
     public String meetingPWD;