🐛 fix syntax error

Author: chfw

.github/workflows/tests.yml

@@ -10,8 +10,8 @@ jobs:
             python-version: [3.6, 3.7, 3.8, 3.9]
             os: [macOs-latest, ubuntu-latest, windows-latest]
             exclude:
-              - os: macos-latest
-               python-version: 3.6
+              - os: macOs-latest
+                python-version: 3.6
 
     runs-on:  ${{ matrix.os }}
     name: run tests