[TD-3990]add Drone CI

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change min rows and max rows to unsigned int and 0 means default.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change offset=0 to get all childtable count
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-4048] <fix>: fix python connector error where ts is null

* [TD-4048] <fix>: bump py connector version to 2.0.9

Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3976]<fix>: taosdemo print each insert performance data.

* [TD-3976]<fix>: taosdemo print insert performance per thread.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

[TD-4059]update case version.py

* [TD-3197] <fix>: fix taosdemo coverity scan issues.

* [TD-3197] <fix>: fix taosdemo coverity scan issue.

fix subscribeTest pids uninitialized.

* [TD-3197] <fix>: fix taosdemo coverity scan issues.

* [TD-3197] <fix>: fix coverity scan issues.

check super tbl info pointer.

* [TD-3197] <fix>: fix coverity scan issues.

move sub tbl query thread join into loop

* [TD-3197] <fix>: fix coverity scan issues.

remove unused variable

* [TD-3197] <fix>: fix coverity scan issues.

use more secure random library

* [TD-3197] <fix>: fix coverity scan issues.

use strncpy for more safe

* [TD-3197] <fix>: fix taosdemo coverity scan issue.

replace arc4random with rand().

* [TD-3197] <fix>: fix coverity scan issues.

check stb info pointer for start time

* [TD-3197] <fix>: fix coverity scan issues.

fix strcpy vulnerability

* [TD-3197] <fix>: fix taosdemo coverity scan issue.

modify taosdemoTest2. try to check database continously.

* [TD-3197] <fix>: taosdemo coverity scan issues.

* [TD-3197] <fix>: fix memory leak when parsing arguments.

* [TD-3197] <fix>: fix cmake strip arguments.

* [TD-3197] <fix>: taosdemo coverity scan.

fix cmake string manipulation.

* [TD-3197]<fix>: taosdemo coverity scan issue.

configDir buffer overwrite.

* [TD-3197]<fix>: coverity scan issue.

taosdump argument validation.

* [TD-3197]<fix>: taosdemo and taosdump coverity scan issues.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change min rows and max rows to unsigned int and 0 means default.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change offset=0 to get all childtable count
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-4054]<fix>: taosdump wrong column note length.

* [TD-4054]<fix>: taosdump wrong column note length.

reserve 2 bytes for NCHAR.

[TD-3994] avoid rpc failure

[td-255]fix bug found by regression test.

Docs/update latest feature

* [TD-4001]<fix>: taosdemo restful segfault.

due to gethostbyname() is not thread-safe.

* fix uninitialized variable when invalid mode.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3968]<fix>: taosdemo datalen should be 16*1024

fix data buffer issue.

* [TD-3968]<fix>: taosdemo datalen should be 16*1024

commend out unused func for debugging purpose in the future

* [TD-3968]<fix>: taosdemo datalen should be 16*1024

comment off unused function

* [TD-3968]<fix>: taosdemo datalen more than 16k.

comment off unused array.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* change few default values.

* [TD-3851]<fix>: taosdemo performance boost.

change max sql len default value to 1024*1024
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

* [TD-3962]<fix>: fix insert special character error in preparedStatement

* change

* change

* change

* change

* change

* change

* [TD-3962]<test>: add test cases for insert special character

* change

* change

* [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.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

[TD-2639] <docs>: fix lib name typo.

[TD-2639] <docs>: fix url link format.

Merge pull request #5936 from taosdata/dependabot/maven/tests/comparisonTest/cassandra/cassandratest/commons-io-commons-io-2.7

Bump commons-io from 2.4 to 2.7 in /tests/comparisonTest/cassandra/cassandratest

Merge pull request #5937 from taosdata/dependabot/maven/tests/comparisonTest/opentsdb/opentsdbtest/commons-io-commons-io-2.7

Bump commons-io from 2.4 to 2.7 in /tests/comparisonTest/opentsdb/opentsdbtest

* [TD-3985]<fix>: taosdemo timestamp step overflow.

* fix specified subscribe test.

* replace potential overflow of int32 to int64

* replace potential int32 overflow variables to int64.

* replace potential int32 overflow variables to int64.

* change max of int16 to int64 after type changed.
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>

Feature/query

[TD-2639] <docs>: update description about performance testing tools …