remove mac x86 naming deviation

Author: Willem Leuverink

.github/workflows/build-php.yml

@@ -51,10 +51,6 @@ jobs:
         if: matrix.os == 'macos-latest'
         run: echo "SPC_BUILD_ARCH=arm64" >> $GITHUB_ENV
 
-      - shell: bash
-        if: matrix.os == 'macos-13'
-        run: echo "SPC_BUILD_ARCH=x86" >> $GITHUB_ENV
-
       - shell: bash
         if: contains(matrix.os, 'macos')
         run: |