Update dependency mysqlclient to v2.2.6

Author: renovate[bot]

pyproject.toml

@@ -79,7 +79,7 @@ sphinx_rtd_theme = "^1.0.0"
 lockfile = "^0.12.2"
 recommonmark = "^0.7.1"
 psycopg2 = {version = "=2.9.6", python = "3.6.* || 3.7.* || 3.8.* || 3.9.*"}
-mysqlclient = {version = "=2.1.1", python = "^3.6"}
+mysqlclient = {version = "=2.2.6", python = "^3.6"}
 tox = "^3.25"
 mypy = {version = "^0.961", python = "^3.6"}
 django-stubs = {version = "^4.0.0", python = "^3.6"}