CI: Add MSYS64 to path, in order to use a different `echo

Author: amotl

.github/workflows/main.yml

@@ -39,6 +39,13 @@ jobs:
           pip install pycodestyle unittest-xml-reporting
           pip install .
 
+      - name: Adjust Windows PATH
+        if: startsWith(matrix.os, 'win')
+        shell: cmd
+        run:   |
+          echo ::add-path::C:\msys64\usr\bin
+          dir C:\msys64\usr\bin
+
       - name: Test
         shell: bash
         run: |