fix: don't let null values in title or keywords break free-text search (#345)

* fix: don't let null values in title or keywords break free-text search

* fix pypgstac version update in stageversion script

Author: hrodmn

docker/pypgstac/bin/stageversion

@@ -45,7 +45,7 @@ cp migrations/pgstac.${VERSION}.sql pgstac.sql
 # Update the version number in the appropriate places
 [[ $VERSION == 'unreleased' ]] && PYVERSION="${OLDVERSION}-dev" || PYVERSION="$VERSION"
 echo "Setting pypgstac version to $PYVERSION"
-cat <<EOD > $PYPGSTACDIR/python/pypgstac/version.py
+cat <<EOD > $PYPGSTACDIR/src/pypgstac/version.py
 """Version."""
 __version__ = "${PYVERSION}"
 EOD