Add SS redirect (#222)

Author: calebofearth

Diff for: README.md

@@ -49,6 +49,7 @@ The Caliptra code base and documentation are split across five repositories:
 | [Caliptra Software](https://github.com/chipsalliance/caliptra-sw) | [Issues](https://github.com/chipsalliance/caliptra-sw/issues),   [PRs](https://github.com/chipsalliance/caliptra-sw/pulls),   [Security advisories](https://github.com/chipsalliance/caliptra-sw/security/advisories)   | Caliptra software (ROM, FMC, runtime firmware), and libraries/tools needed to build and test |
 | [Caliptra DPE](https://github.com/chipsalliance/caliptra-dpe)     | [Issues](https://github.com/chipsalliance/caliptra-dpe/issues),  [PRs](https://github.com/chipsalliance/caliptra-dpe/pulls),  [Security advisories](https://github.com/chipsalliance/caliptra-dpe/security/advisories)  | An implementation of a TCG DICE Protection Environment profile |
 | [Caliptra U-Reg](https://github.com/chipsalliance/caliptra-ureg)  | [Issues](https://github.com/chipsalliance/caliptra-ureg/issues), [PRs](https://github.com/chipsalliance/caliptra-ureg/pulls), [Security advisories](https://github.com/chipsalliance/caliptra-ureg/security/advisories) | General-purpose libraries and tools for manipulating MMIO registers from Rust |
+| [Caliptra Subsystem](https://github.com/chipsalliance/caliptra-ss)| [Issues](https://github.com/chipsalliance/caliptra-ss/issues), [PRs](https://github.com/chipsalliance/caliptra-ss/pulls), [Security advisories](https://github.com/chipsalliance/caliptra-ss/security/advisories) | Caliptra Subsystem including Manufacturer Control Unit (MCU) and peripherals |
 
 The GitHub config parameters for all of the branches are documented in a [local
 file](https://github.com/chipsalliance/Caliptra/blob/main/GitHubRules.md).