Increase timeout to 3 hours

The clashes between the matrix jobs in obtaining a working free proxy
may increase the time it takes to finish the tests.

Author: arunkannawadi

.github/workflows/pythonpackage.yml

@@ -14,7 +14,7 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-    timeout-minutes: 120
+    timeout-minutes: 180
     strategy:
       matrix:
         python-version: [3.8]