[submodule]: update sonic-swss (#5002)

* d2bab10 2020-07-19 | [vstest]: use BytesIO for file operations [lguohan]
* 982c9a3 2020-07-18 | [vstest]: fix vstest for python3 (#1354) [lguohan]
* ffa0dc3 2020-07-16 | [vstest]: clean up processes in server namespace at start (#1353) [lguohan]
* b16368c 2020-07-15 | [aclorch.cpp] Handle all the ACL redirect requests in AclRuleL3::validateAddAction()  (#1278) [madhanmellanox]
* 310e0aa 2020-07-15 | [portsorch,intfsorch] add port, rif rates FC groups (#1201) [Mykola F]
* 5ddea37 2020-07-09 |  [NAT]: Update NAT conntrack entries from natmgr instead of natorch (#1274) [Akhilesh Samineni]
* 94c622f 2020-07-07 | [aclorch] Use IPv6 Next Header internally for protocol number on MLNX platform (#1343) [Danny Allen]
*   82d36c4 2020-07-07 | support swss vstest in python3 [lguohan]
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| * ff04e6d 2020-06-27 | [doc]: update instruction to run vstest under python3 [Guohan Lu]
| * c90b281 2020-07-05 | [vstest]: reuse dvs setReadOnlyAttr in test_crm.py [Guohan Lu]
| * 8807b40 2020-07-05 | [vstest]: fix string format compatibility issue for python2 and swig [Guohan Lu]
| * 26efbcf 2020-07-04 | [vstest]: change float division to integer division [Guohan Lu]
| * 6adaf2e 2020-07-04 | [vstest]: change time.clock() to time.time() [Guohan Lu]
| * 9c71203 2020-07-04 | [vstest]: let redis decodes the response to be string instead of bytes [Guohan Lu]
| * c7c63ee 2020-06-27 | [vstest]: change from platform to distro [Guohan Lu]
| * d7ff1ad 2020-06-27 | [vstest]: upgrade swss vs tests to python3 [Guohan Lu]
* | 2ebd44e 2020-07-03 | [sonic-swss] ARMHF warning fixes (#1325) [arheneus@marvell.com]
* | 10ad70c 2020-07-02 | [swss] Add support for gearbox phys (#1321) [Syd Logan]

Signed-off-by: Guohan Lu <lguohan@gmail.com>