Update requirements.txt
Update requirements.txt

Adding svgwrite for visualization
google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools