Log Message:
py-xlsxwriter: updated to 1.3.6

Release 1.3.6:
* Added the worksheet :func:`unprotect_range()` method to allow ranges within
  a protected worksheet to be unprotected.
* There are now over 1500 test cases in the test suite, including 900 tests
  that compare the output from XlsxWriter, byte for byte, against test files
  created in Excel. This is to ensure the maximum possible compatibility with
  Excel.

Release 1.3.5:
* Fixed issue where relative url links in images didn't work.
* Added ``use_zip64`` as a constructor option.
* Added check, and warning, for worksheet tables with no data row.
  Either with or without a header row.
* Add a warning when the string length in :func:`write_rich_string()` exceeds
  Excel's limit.

Release 1.3.4:
* Replaced internal MD5 digest used to check for duplicate images with a SHA256
  digest to avoid issues on operating systems such as Red Hat in FIPS mode
  which don't support MD5 for security reasons.