Publish ratified version 1.0.0

Publish ratified version 1.0.0.

Version 1.0.0_rc6 release

Remove H/U mode from PLIC spec.

Version 1.0.0_rc5 release

Update spec to revise the unclear description of "register width" (chapter 4)
See the changelog in PDF file.

Version 1.0.0_rc4 release

Update specification to Frozen state.

Version 1.0.0_rc3 release

Revised Copyright and license information.

Version 1.0.0_rc2 release

This release fixes the below issues,

• Revised the copyright statements to follow section 3.3 in Appendix A "INTELLECTUAL PROPERTY RIGHTS POLICY " of the RISC-V Regulations.
• Correct the offsets of PLIC Interrupt Enable Bits memory map.

Version 1.0.0_rc1 release

Version 1.0.0_rc1 release for the public review.