Fix pytest installation in CI script

build-and-test-py-project.sh

@@ -55,9 +55,7 @@ export XDG_CACHE_HOME=$HOME/.cache/$CI_RUNNER_ID
 $PIP install --upgrade pip
 $PIP install setuptools
 
-# Pinned to 3.0.4 because of https://github.com/pytest-dev/pytest/issues/2434
-# Install before a newer version gets pulled in as a dependency
-#$PIP install pytest==3.0.4 pytest-warnings==0.2.0
+$PIP install pytest
 
 if test "$EXTRA_INSTALL" != ""; then
   for i in $EXTRA_INSTALL ; do