updating github action

Author: maxkahan

.github/workflows/ot.yml

@@ -5,15 +5,15 @@ on: [push]
 jobs:
   test:
 
-    runs-on: ubuntu-latest
+    runs-on: "ubuntu-latest"
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8.8, 3.9]
+        python-version: ["3.6", "3.7", "3.8.8", "3.9"]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies