Remove Simd-json (#228)

This mirrors the serenity pr https://github.com/serenity-rs/serenity/pull/2735.

.github/workflows/ci.yml

@@ -35,7 +35,6 @@ jobs:
           - Windows
           - driver only
           - gateway only
-          - simd json
         include:
           - name: beta
             toolchain: beta
@@ -53,10 +52,6 @@ jobs:
           - name: gateway only
             features: gateway serenity tungstenite rustls
             dont-test: true
-          - name: simd json
-            features: simd-json serenity tungstenite rustls driver gateway serenity?/simd_json
-            rustflags: -C target-cpu=native
-            dont-test: true
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3