ci: fight CI flakiness by using pip --user

Installing packages with `pip` using the `--user` flag may be the way
to avoid permission issues. Let's try this out.

Author: wprzytula

.github/workflows/integration-tests.yml

@@ -55,9 +55,8 @@ jobs:
       - name: Install ccm and get simulacron
         run: |
           wget https://github.com/datastax/simulacron/releases/download/0.12.0/simulacron-standalone-0.12.0.jar -O ~/simulacron.jar
-          pip install psutil
-          sudo pip install --upgrade psutil
-          pip install https://github.com/scylladb/scylla-ccm/archive/master.zip
+          pip install --user --upgrade psutil
+          pip install --user https://github.com/scylladb/scylla-ccm/archive/master.zip
       - name: Build
         run: ${{ matrix.settings.build }}
         shell: bash