Force CentOS to install Python 3

Author: devongovett

azure-pipelines-template.yml

@@ -35,6 +35,10 @@ jobs:
         watchman -v
       displayName: Install Watchman
 
+  - ${{ if eq(parameters.name, 'CentOS7') }}:
+    - script: sudo yum install -y python3
+      displayName: Install Python3
+
   - script: npm install --build-from-source
     displayName: Install dependencies
   - script: npm test