Adding python3.9 wheels release

base on this draft PR/branch
pypa/cibuildwheel#382

currently skipping windows for python3.9, since the
tests are not working

.travis.yml

@@ -102,7 +102,7 @@ jobs:
       os: osx
       env:
         - CIBW_BEFORE_TEST_MACOS="pip install -r {project}/test-requirements.txt pytest"
-        - CIBW_BUILD="cp37* cp38*"
+        - CIBW_BUILD="cp37* cp38* cp39*"
       before_install:
         - brew install libev
       language: shell
@@ -122,7 +122,9 @@ jobs:
     - name: CPython Windows 64
       os: windows
       language: shell
-      env: CIBW_BUILD="cp*win_amd64"
+      env:
+        - CIBW_BUILD="cp*win_amd64"
+        - CIBW_SKIP="cp39*"
       before_install:
         - choco install python --version 3.8.0
         - export PATH="/c/Python38:/c/Python38/Scripts:$PATH"
@@ -132,7 +134,9 @@ jobs:
     - name: CPython Windows 32
       os: windows
       language: shell
-      env: CIBW_BUILD="cp*win32"
+      env:
+        - CIBW_BUILD="cp*win32"
+        - CIBW_SKIP="cp39*"
       before_install:
         - choco install python --version 3.8.0
         - export PATH="/c/Python38:/c/Python38/Scripts:$PATH"
@@ -162,7 +166,8 @@ jobs:
       if: type != pull_request AND (branch = master OR (tag =~ /^.*-scylla$/))
 
 install:
-  - python3 -m pip install cibuildwheel==1.3.0
+  # - python3 -m pip install cibuildwheel==1.3.0
+  - python3 -m pip install git+https://github.com/joerick/cibuildwheel.git@python3.9
 
 script:
   # build the wheels, put them into './wheelhouse'