meetup: removed public class modifiers as per #1081

* "#1081 Removed public class modifiers"

* Changed Meetup method to private per comments on Pull Request #1082

* Made Meetup method public again as it did not pass the checks for Pull Request #1082.

* Changed MeetupTest.java to private per comments on Pull Request #1082

* Made MeetupTest public again as it failed testing.

* Made Meetup method package-private per comments on Pull Request #1082.

* Corrected access modifiers per suggestions on Pull Request #1082.

Removed package-private from Meetup method and removed private from
cycleToPrev and cycleToNext methods.

* Added private access levels back to cycleToPrev and cycleToNext.

Per feedback on pull request #1082 added the private access levels back
to these two methods.

exercises/meetup/.meta/src/reference/java/Meetup.java

 import java.time.DayOfWeek;
 
 
-public class Meetup {
+class Meetup {
     private final LocalDate startOfMonth;
 
-    public Meetup(int monthOfYear, int year) {
+    Meetup(int monthOfYear, int year) {
         startOfMonth = LocalDate.of(year, monthOfYear, 1);
     }
 

exercises/meetup/.meta/src/reference/java/MeetupSchedule.java

-public enum MeetupSchedule {
+enum MeetupSchedule {
     FIRST,
     SECOND,
     THIRD,

exercises/meetup/src/main/java/MeetupSchedule.java

-public enum MeetupSchedule {
+enum MeetupSchedule {
     FIRST,
     SECOND,
     THIRD,