go1.20+: Refuse to work if cgo is enabled

On go1.20+ it is no longer possible to directly copy a cgo-enabled
library into a docker container. For this reason, this commit adds a
flag to commands that automatically make them fail with an appropriate
message if cgo is enabled.

.github/workflows/test.yaml

@@ -36,7 +36,7 @@ jobs:
           go test ./...
       - name: Build executable
         run: |
-          go build -o wdcli ./cmd/wdcli
+          CGO_ENABLED=0 go build -o wdcli ./cmd/wdcli
       - name: Upload Release
         uses: softprops/action-gh-release@v1
         if: startsWith(github.ref, 'refs/tags/')