docs: update README to 174 fixtures, v2.2.1+ (Go v1.3.1)

Author: blackwell-systems

README.md

@@ -211,7 +211,7 @@ GCF wins 15/16 datasets on the expanded [token efficiency benchmark](https://git
 
 **Zero runtime dependencies. Permanently.** All six implementations depend only on their language's standard library. No transitive dependencies. No supply chain risk. This is a permanent commitment: GCF will never take on external runtime dependencies. MIT licensed. All implementations support both generic profile (`encodeGeneric`) and graph profile (`encode`). CLI included in all 6 languages.
 
-**Specification:** [SPEC v3.2 Stable](https://github.com/blackwell-systems/gcf/blob/main/SPEC.md) with 173 conformance fixtures, 43,000,000,000+ lossless round-trips verified across 5 formats and 6 languages. All implementations at v2.2.0+ (Go v1.3.0). Cross-language 6x6 matrix verified.
+**Specification:** [SPEC v3.2 Stable](https://github.com/blackwell-systems/gcf/blob/main/SPEC.md) with 174 conformance fixtures, 43,000,000,000+ lossless round-trips verified across 5 formats and 6 languages. All implementations at v2.2.1+ (Go v1.3.1). Cross-language 6x6 matrix verified.
 
 ## License