macos 10.15 deprecated by gh actions

.github/workflows/test-macos.yml

@@ -71,57 +71,3 @@ jobs:
         shell: bash
         run: |
           make -j${{ env.procs }} test CXXSTD=${{ matrix.cpp_std }} CC=cc CXX=cc LD=cc
-
-
-  test-macos-homebrew:
-    runs-on: ${{ matrix.os.id }}
-    strategy:
-      matrix:
-        os:
-          - { id: macos-10.15, name: Catalina }
-        cpp_std:
-          - 'c++17'
-        compiler:
-          - gcc
-      fail-fast: false
-    steps:
-      - name: Install Dependencies
-        run: |
-          brew install bison flex gawk libffi pkg-config bash
-
-      - name: Runtime environment
-        shell: bash
-        env:
-          WORKSPACE: ${{ github.workspace }}
-        run: |
-          echo "GITHUB_WORKSPACE=`pwd`" >> $GITHUB_ENV
-          echo "$GITHUB_WORKSPACE/.local/bin" >> $GITHUB_PATH
-          echo "$(brew --prefix bison)/bin" >> $GITHUB_PATH
-          echo "$(brew --prefix flex)/bin" >> $GITHUB_PATH
-          echo "procs=$(sysctl -n hw.ncpu)" >> $GITHUB_ENV
-
-      - name: Setup compiler
-        shell: bash
-        run: |
-          brew install ${{ matrix.compiler }}
-          CC=${COMPILER/@/-}
-          CXX=${CC/#gcc/g++}
-          echo "CC=$CC" >> $GITHUB_ENV
-          echo "CXX=$CXX" >> $GITHUB_ENV
-        env:
-          COMPILER: ${{ matrix.compiler }}
-
-      - name: Tool versions
-        shell: bash
-        run: |
-          $CC --version
-          $CXX --version
-
-      - name: Checkout Yosys
-        uses: actions/checkout@v2
-
-      - name: Build yosys
-        shell: bash
-        run: |
-          make config-gcc
-          make -j${{ env.procs }} CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC