Fix str of RayTaskError (ray-project#5878)

* fix key error

* fix

[rllib] Properly flatten 2-d observations as input to FCnet (ray-proj…

…ect#5733)

bump version to 0.7.5

[rllib] Revert [rllib] Port DDPG to the build_tf_policy pattern (ray-…

…project#5626)

Revert "[gRPC] Migrate raylet client implementation to grpc (ray-proj…

…ect#5120)"

This reverts commit 40395ac.

Revert "Bump version to 0.8.0.dev2 (ray-project#5069)"

This reverts commit d7ccfbe.

Upload wheels on Travis to branchname/commit_id. (ray-project#4949)

Bump version to 0.7.0 (ray-project#4791)

Revert "Updating zero capacity resource semantics (ray-project#4555)"

This reverts commit 0f42f87.

Bump version from 0.7.0.dev1 to 0.6.5. (ray-project#4461)