Update README and versions for 21.03 release (triton-inference-server…

…#2664)

Specify correct TF2 container tag

Update README for 20.12 release

Update README and versions for 20.11 release

Fix build when --upstream-container-version not specified (triton-inf…

…erence-server#2175)

Update README and versions for 20.09 release

Fix batch input shape

Update README and versions for 20.08 release

Update README and versions for 20.07 release

Update README and versions for 20.07-v1 release