[td-4611]<fix>: fix bug during aggregate in outer query.
[td-255]fix memory leaks and suppress warning by valgrind.

* [TD-4480]<fix>: fix DatabaseMetaData has wrong column index bug

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* change test cases

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* change jdbc version

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Bumps httpclient from 4.5.8 to 4.5.13.

---
updated-dependencies:
- dependency-name: org.apache.httpcomponents:httpclient
  dependency-type: direct:production
...
Signed-off-by: Ndependabot[bot] <support@github.com>
Co-authored-by: Ndependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* [TD-4025]<fix>: travis ci broken due to valgrind dependency missed.

modify smoketest.sh to python3.8

* [TD-4025]<fix>: travis ci broken due to ubuntu 20.04 repo issue.

* [TD-4025]<fix>: travis ci broken due to ubuntu 20.04 repo issue.

* [TD-4025]<fix>: travis ci broken due to ubuntu 20.04 repo issue.

* [TD-4025]<fix>: travis ci broken due to valgrind dependency missed.

change focal to bionic.

* [TD-4025]<fix>: travis ci broken due to ubuntu 20.04 repo issue.

cherry pick from master.

* don't check maven on windows for appveyor.

* fix timezone build error with clang/linux.

* add .appveyor.yml back.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>