v0.2.3

Commits

• c05524c: unify vocab (Zhiyuan Chen)
• c24fbf1: vectorize graph topology (Zhiyuan Chen)
• f2b3979: implement tensor maximum weight matching (Zhiyuan Chen)
• 363a8da: add linear sum assignment (Zhiyuan Chen)
• ce62f31: remove polyfill.io script (Zhiyuan Chen)
• 4b87832: add labeled graph isomorphism and optimize graph operations (Zhiyuan Chen)