Update Poetry install command in CI config

Updated the poetry install command in the continuous integration configuration (".github/workflows/ci.yml"). Removed the other flags and just added the "--sync" option for the Poetry install command to enforce a correct and complete installation of dependencies.

.github/workflows/ci.yml

@@ -59,7 +59,7 @@ jobs:
           cache: 'poetry'
 
       - name: Install dependencies
-        run: poetry install --only main,dev --no-interaction --no-ansi
+        run: poetry install --no-interaction --no-ansi --sync
 
       - name: Run unittests
         run: python tests/testing.py