switch from Appveyor to Github Actions for Windows testing

.github/workflows/windows.yml

@@ -0,0 +1,38 @@
+# cribbed from https://stackoverflow.com/questions/72367353/testing-perl-on-windows-with-github-actions
+
+on: [push, pull_request]
+name: Windows
+
+jobs:
+  build:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        perl-version:
+          - '5.20'
+          - '5.22'
+          - '5.24'
+          - '5.26'
+          - '5.28'
+          - '5.30'
+          - '5.32'
+          - '5.34'
+          - 'latest'
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Perl
+        run: |
+          choco install strawberryperl
+          echo "C:\strawberry\c\bin;C:\strawberry\perl\site\bin;C:\strawberry\perl\bin" >> $GITHUB_PATH
+      - name: perl -V
+        run: perl -V
+      - name: Install Dependencies
+        run: |
+          cpanm ExtUtils::MakeMaker Test::Pod Test::Pod::Coverage || cat $HOME/.cpanm/work/*/build.log
+          cpanm --installdeps . || cat $HOME/.cpanm/work/*/build.log
+      - name: Run Tests
+        run: |
+          perl Makefile.PL
+          make test TEST_VERBOSE=1
+