do not build the C API on x86 OSX (#237)

* do not build on x86 OSX

* update readme

* Apply suggestions from code review

.github/workflows/release.yml

@@ -17,8 +17,9 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-latest-large
-            target_arch: x86_64-apple-darwin
+          # deactivated for now, the x86 workers are more expensive
+          # - os: macos-latest-large
+          #   target_arch: x86_64-apple-darwin
           - os: macos-latest
             target_arch: aarch64-apple-darwin
           - os: ubuntu-latest

biscuit-capi/README.md

@@ -16,7 +16,7 @@ You can then link against the generated library in your C code.
 
 ### Downloading pre-built binaries
 In the [releases section](https://github.com/biscuit-auth/biscuit-rust/releases) of this repository, you can find pre-built binaries for the C API.
-Currently, only Linux x86_64 and MacOS (x86 + arm) are provided.
+Currently, only Linux x86_64 and MacOS (arm) are provided.
 
 ### Running the tests