chore: document a workaround for html5validator.

[skip ci]

Author: php-coder

docs/decisions-log.md

@@ -4,3 +4,4 @@
 | --------- | ----------- |
 | 09.02.2020 Workaround | **pdd** fails to parse files in charsets other than UTF-8 with error `invalid byte sequence in UTF-8`. Workaround: exclude `src/test/wiremock` directory. Bug: [yegor256/pdd#143](https://github.com/yegor256/pdd/issues/143) Commits: [30aab7d](https://github.com/php-coder/mystamps/commit/30aab7dc8c265804efef382422e7cae9e53187f3), [ab563b6](https://github.com/php-coder/mystamps/commit/ab563b653279625120121babccdfd915181ee46d) |
 | 07.02.2020 Workaround | [php-coder/mystamps#1248](https://github.com/php-coder/mystamps/issues/1248): **wiremock** logs warnings for static resources when there is no stub mapping. Workaround: create mappings for such resources. Bug: [tomakehurst/wiremock#1247](https://github.com/tomakehurst/wiremock/issues/1247) Commits: [0018ad4](https://github.com/php-coder/mystamps/commit/0018ad44a21379b8179f94e954795c66b6d50bbc) |
+| 24.11.2019 Workaround | [php-coder/mystamps#1156](https://github.com/php-coder/mystamps/issues/1156) After updating **html5validator** to 0.3.2, the `--ignore-re` has stopped to work. Workaround: revert and pin the version to 0.3.1 Bug: [svenkreiss/html5validator#64](https://github.com/svenkreiss/html5validator/issues/64) [9a0d695](https://github.com/php-coder/mystamps/commit/9a0d695ccac1deeba0c4280779bbac11ebf3ac4d) |