AC

1. Review and merge the Decimal128 fix (NODE-5546)
   SUBTASK:
2. Get an alpha version of BSON released (already have mongo-client-encryption alpha) - port over the driver gh action for this
   SUBTASK:
3. Update driver main to use the bson alpha
4. Update driver main to use legacy - use mongodb-legacy#main
5. Release another alpha of the driver to get updated bson
6. Update legacy driver to depend on driver alpha and let those tests run
   SUBTASK:
7. Create release notes for bson and fle v6
8. Wait for Shell to finish testing alphas
   SUBTASK:
9. Release mongo-client-encryption 6.0.0
10. Release bson 6.0.0
    SUBTASK:
11. Update package.json in the driver to use the new bson and fle major versions (update any manual references to alphas in CI for fle)
    SUBTASK:
12. Ensure driver migration guide is merged and release notes are correct
13. Release V6 of the driver
14. Update legacy driver to use V6 of the driver
15. Release legacy driver V6
16. Update driver to use V6 of legacy instead of a git branch