Add 39 to ci (#16)

* add Python 3.9 to the CI as the main version

* take out numpy dependency: their latest release doesn't provide wheels for 3.6, and I don't want to drop support for 3.6 yet

.github/workflows/run_tests.yml

@@ -14,16 +14,20 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, macos-latest, ubuntu-latest]
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.6, 3.7, 3.8, 3.9]
         exclude:
           - os: macos-latest
             python-version: 3.6
           - os: macos-latest
             python-version: 3.7
+          - os: macos-latest
+            python-version: 3.8
           - os: windows-latest
             python-version: 3.6
           - os: windows-latest
             python-version: 3.7
+          - os: windows-latest
+            python-version: 3.8
 
     steps:
     - uses: actions/checkout@v2

requirements.txt

@@ -1,7 +1,6 @@
 skia-python==87.1
 fonttools[unicode]==4.21.1
 uharfbuzz==0.15.0
-numpy==1.20.1
 python-bidi==0.4.2
 unicodedata2==13.0.0.post2
 skia-pathops==0.6.0.post2