Fix homebrew include path.

Author: stefanseefeld

.github/workflows/test-osx.yml

@@ -32,15 +32,15 @@ jobs:
         faber -v
         sed -e "s/\$PYTHON/python/g" .ci/faber > ~/.faber
         faber \
-          --with-boost-include=/opt/homebrew/Cellar/boost/1.86.0/include \
+          --with-boost-include=$(brew --prefix boost)/include \
           --builddir=build \
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \
           -j`sysctl -n hw.ncpu`
     - name: test
       run: |
         faber \
-          --with-boost-include=/opt/homebrew/Cellar/boost/1.86.0/include \
+          --with-boost-include=$(brew --prefix boost)/include \
           --builddir=build\
           cxx.name=${{ matrix.cxx }} \
           cxxflags=-std=${{ matrix.std }} \