Remove mingw from GHA tests: it's failing even basic programs.

.github/workflows/ci.yml

@@ -130,47 +130,6 @@ jobs:
       - name: Test
         run: ../../../b2 toolset=${{ matrix.toolset }} cxxstd=03,11,14,17,2a
         working-directory: ../boost-root/libs/config/test
-  windows_mingw:
-    runs-on: windows-latest
-    defaults:
-      run:
-        shell: cmd
-    strategy:
-      fail-fast: false
-      matrix:
-        toolset: [ gcc ]
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          fetch-depth: '0'
-      - uses: mstachniuk/ci-skip@v1
-        with:
-          commit-filter: '[skip ci];[ci skip];[CI SKIP];[SKIP CI];***CI SKIP***;***SKIP CI***;[apple];[Apple];[APPLE];[linux];[Linux];[LINUX]'
-          commit-filter-separator: ';'
-          fail-fast: true
-      - name: Checkout main boost
-        run: git clone -b develop --depth 1 https://github.com/boostorg/boost.git ../boost-root
-      - name: Update tools/boostdep
-        run: git submodule update --init tools/boostdep
-        working-directory: ../boost-root
-      - name: Copy files
-        run: xcopy /s /e /q %GITHUB_WORKSPACE% libs\config
-        working-directory: ../boost-root
-      - name: Update Dependencies
-        run: git submodule update --init tools/build tools/boost_install libs/headers libs/detail libs/core libs/assert libs/type_traits
-        working-directory: ../boost-root
-      - name: Bootstrap
-        run: bootstrap
-        working-directory: ../boost-root
-      - name: Generate headers
-        run: b2 headers
-        working-directory: ../boost-root
-      - name: Config info
-        run: ..\..\..\b2 print_config_info cxxstd=03,11,14,17 address-model=64 toolset=gcc
-        working-directory: ../boost-root/libs/config/test
-      - name: Test
-        run: ..\..\..\b2 --hash address-model=64 toolset=gcc
-        working-directory: ../boost-root/libs/config/test
   windows_msvc_14_0:
     runs-on: windows-latest
     defaults: