travis: Fix python on macos runner
travis: Fix python on macos runner

google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,or-tools/or-tools,google/or-tools,google/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools