crt update (#271)

Update aws-crt-cpp to v0.13.6 to bring up the following:

### BUGFIX

  -  Don't run aws-lc's codegen at build time, it just introduces complexity.
  -  Some characters were not correctly URI-encoded
  -  Fix crash when peer hangs up immediately following first non-TLS write.
  -  Fix issue where TLS context initialization could fail on linux due to passing in buffers that weren't properly zero-terminated at their final length.
  -  OpenSSL libcrypto.a detection fixes

### Optimization

  -  Only using extra warning and werror flags on Debug build type
  -  Add support to store and pass SDK Name & Version as a metric to IoT cloud

Author: TingDaoK