Update .travis.yml

- Windows test uses 3.9.6 now
- Intentation changes

.travis.yml

@@ -19,9 +19,9 @@ matrix:
       python: "3.9"
     - os: "windows"
       language: shell
-                  python: "3.8"
-                  env: "PATH=/c/python38:/c/python38/Scripts:$PATH"
+      python: "3.9"
+      env: "PATH=/c/python39:/c/python39/Scripts:$PATH"
       before_install:
-                          - choco install python --version=3.8.6
-                          - cp /c/python38/python.exe /c/python38/python3.exe
-                  script: tox -e py38
+              - choco install python --version=3.9.6
+              - cp /c/python39/python.exe /c/python39/python3.exe
+      script: tox -e py39