Fmaster/lihui

Merge from develop into master

[update version info]

TD-1205 add error code to crash_gen.py

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TD-1174: jdbc without host ip

fix two case of 'unexpected generic error in RPC'

Master

fix td-1189

[TD-1048]

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log an error message if failed to call `gethostname`.
don't update epset if peer returns empty epset.

Merge pull request #3182 from taosdata/feature/sangshuduo/add-a-badge-to-indicate-docker-pull-number

add a badge to indicate docker image pull number.

[TECO-7]

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