ci: use aarch64 toolchain on macOS latest

Author: FreezyLemon

.github/workflows/matroska.yml

@@ -77,12 +77,12 @@ jobs:
     strategy:
       matrix:
         toolchain:
-         - stable-x86_64-apple-darwin
+         - stable-aarch64-apple-darwin
          - stable-x86_64-unknown-linux-gnu
          - stable-x86_64-pc-windows-msvc
          - stable-i686-pc-windows-msvc
         include:
-         - toolchain: stable-x86_64-apple-darwin
+         - toolchain: stable-aarch64-apple-darwin
            os: macOS-latest
          - toolchain: stable-x86_64-unknown-linux-gnu
            os: ubuntu-latest