Bump up to v0.2.6 (vllm-project#2157)

Bump up to v0.2.5 (vllm-project#2095)

Bump up to v0.2.4 (vllm-project#2034)

Bump up to v0.2.3 (vllm-project#1903)

Bump up to v0.2.2 (vllm-project#1689)

Bump up the version to v0.2.1 (vllm-project#1355)

Bump up the version to v0.2.0 (vllm-project#1212)

Bump up the version to v0.1.7 (vllm-project#1013)

Bump up the version to v0.1.6 (vllm-project#989)