Use Windows-compatible installation steps for IDAES extensions

.github/workflows/main.yml

@@ -44,7 +44,19 @@ jobs:
         idaes --version
     - name: Install IDAES extensions
       run: |
-        idaes get-extensions --platform ubuntu1804
+        idaes get-extensions --verbose
+        # NOTE: these commands are Unix-shell specific 
+        # and will need to be changed if we want to test on CMD.exe/Powershell
+        find $(idaes data-directory) -ls
+        # add bin directory to $PATH (only valid for subsequent steps)
+        echo "$(idaes bin-directory)" >> $GITHUB_PATH
+    - name: Test access to executables
+      run: |
+        if [ "$RUNNER_OS" == "Windows" ]; then
+            ipopt.exe -v
+        else
+            ipopt -v
+        fi
     - name: Run non-integration tests
       run: |
         pytest --verbose -m "not integration" tests/