feat(fcm): Implement `sendEach`, `sendEachAsync`, `sendEachForMulticast` and `sendEachForMulticastAsync`#785

Merged

Doris-Ge merged 3 commits intofcm-batch-sendfrom

remotes/dorisge/fcm-batch-send

Jun 2, 2023

Commits on Mar 17, 2023

Add org.hamcrest as dependency for unit tests
Doris-Ge
committed
Implement sendEach, sendEachAsync, sendEachForMulticast and sendEachForMulticastAsync
Doris-Ge
committed

Commits on May 30, 2023

Add integration tests for batch-send re-implementation:
Doris-Ge
committed