Update the changelog.

Update the changelog.

Update the changelog.

* Support PHP 8.0 / 8.1.

* Fix non-optional params on some objects and return type declarations.

* Fix an OID encoding case when the second component would be near or…

… over the max int as defined by PHP.

* Fix the encoding / decoding of OIDs when the first / second compone…

…nt is more than one byte (found by @danielmarschall)

* Fix the length-of-length check for a partial PDU with long definite…

… encoding under certain circumstances.

More performance optimizations in the encoding / decoding process for…

… large amounts of data structures.

* Performance and memory improvements.

* Removed the 'trailing data' aspect of decoded types.
* Added a 'getLastPosition' method for encoders. Returns the last position in the byte stream the decoder stopped at.
* Removed the 'constructed_only' and 'primitive_only' options for the encoder.

Additional minor performance improvements.