Dropping duplicate runs from travis CI

- Drop the duplicate runs from travis that github actions now cover.
- Add additional ppc64le entries for 3.7, 3.8, 3.9

.travis.yml

@@ -1,29 +1,16 @@
 language: python
 matrix:
   include:
-    - os: windows
-      language: sh
-      python: "3.8"
-      env: "PATH=/c/Python38:/c/Python38/Scripts:$PATH"
-      # Perform the manual steps on windows to install python3
-      before_install:
-        - choco install python --version=3.8.6
-        - python -m pip install --upgrade pip
-      before_script:
-        - export TOXENV=py38
-    - python: "2.7"
     - python: "3.4"
-    - python: "3.5"
+    - python: "2.7"
+      arch: ppc64le
     - python: "3.6"
+      arch: ppc64le
     - python: "3.7"
+      arch: ppc64le
     - python: "3.8"
-    - python: "3.9"
-    - python: "nightly"  # 3.10
-      before_script:
-        - export TOXENV=py310
-    - python: "2.7"
       arch: ppc64le
-    - python: "3.6"
+    - python: "3.9"
       arch: ppc64le
 install:
   - python -m pip install tox