Scalar Cryptography v1.0.1

This is the formal release of v1.0.1 of the RISC-V Scalar Cryptography extensions.

This specification's status is Ratified.

Changes since the previous version:

• Remove -rc4 from the minimum supported version of each instruciton. These now all point to v1.0.0 (I.e. the first ratified verison).
• Fix three typos to show that c.srli, c.srai, and c.slli are Zkt instructions in RV64. See #149, #152.
• Include this in a new change-log section.