Update liboqs to version 0.7.0

Changes in liboqs-rust
======================

* Updates to `liboqs` 0.7.0 (see below)
* New feature flags for each algorithm
    * Default features include `kems` and `sigs` which in turn include
      all algorithms.

`liboqs` changelog:
-------------------

This release continues from the 0.6.0 release of liboqs.

**Key encapsulation mechanisms**

- Update BIKE to Round 3 (version 3.2) -- add BIKE1, BIKE3, remove BIKE1-L1-CPA, BIKE1-L1-FO, BIKE1-L3-CPA, BIKE1-L3-FO
- Update NTRU Prime implementation
- Update SIKE implementation
- Remove OQS\_KEM\_DEFAULT alias

**Digital signature schemes**

- Remove OQS\_SIG\_DEFAULT alias

**Other changes**

- Allow liboqs to build on other architectures, with preliminary builds on ppc64le and x86.
- Support for building liboqs on Apple Silicon
- New algorithm datasheets with more details on implementations.
- Optimized SHA-256 implementation on ARMv8 with crypto extensions.

Author: thomwiggers