CI: Add conda-windows job

Author: mrkn

.github/workflows/ci.yml

@@ -133,3 +133,57 @@ jobs:
       env:
         PYTHON: python
       shell: bash -l {0}
+
+  conda-windows:
+    name: conda:windows-latest/${{ matrix. ruby }}/${{ matrix.python }}
+    runs-on: windows-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+        - "3.0"
+        python:
+        - 3.8
+
+    defaults:
+      run:
+        shell: pwsh
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 1
+
+    - uses: conda-incubator/setup-miniconda@v2
+      with:
+        activate-environment: test
+        python-version: ${{ matrix.python }}
+
+    - run: set
+      shell: cmd
+
+    - name: Add conda's DLL path
+      run: |
+        echo $env:CONDA\Library\bin >> $GITHUB_PATH
+        echo $env:CONDA_PREFIX\Library\bin >> $GITHUB_PATH
+
+    - uses: ruby/setup-ruby@v1
+      if: matrix.ruby_version != 'master-nightly'
+      with:
+        ruby-version: ${{ matrix.ruby }}
+
+    - run: conda install numpy
+
+    - run: python -c 'import numpy; print(numpy)'
+
+    - run: bundle install
+
+    - run: rake compile
+
+    - run: python lib/pycall/python/investigator.py
+
+    - run: |
+        rake
+      env:
+        PYTHON: python