Bug fix update to 4.3.4a

pdu.c: Fix issue with 269 delta in internal coap_remove_option()

Update unit tests to check for a delta of 13 / 269.

Update version to release 4.3.3

RIOT: Update PKG_VERSION to point to 4.3.2 code

RIOT: Update PKG_URL and PKG_VERSION to latest 4.3.2rc2 code

RIOT: Update PKG_URL and PKG_VERSION to latest 4.3.2rc1 code

Update version to release 4.3.1

Tag release candidate 2 for version 4.3.1

Tag release candidate 1 for version 4.3.1

Bump version to 4.3.0