Bump pytest-variables from 1.7.1 to 1.9.0 in /requirements

Bumps [pytest-variables](https://github.com/pytest-dev/pytest-variables) from 1.7.1 to 1.9.0.
- [Release notes](https://github.com/pytest-dev/pytest-variables/releases)
- [Changelog](https://github.com/pytest-dev/pytest-variables/blob/master/CHANGES.rst)
- [Commits](https://github.com/pytest-dev/pytest-variables/compare/v1.7.1...v1.9.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements/dev.txt

@@ -100,9 +100,9 @@ pytest-html==2.0.1 \
 pytest-metadata==1.8.0 \
     --hash=sha256:c29a1fb470424926c63154c1b632c02585f2ba4282932058a71d35295ff8c96d \
     --hash=sha256:2071a59285de40d7541fde1eb9f1ddea1c9db165882df82781367471238b66ba
-pytest-variables==1.7.1 \
-    --hash=sha256:59c00b95779657532ac5f8209b28b5d447c8b4bc4210c1d6bdf9a42aa201f9b0 \
-    --hash=sha256:7808b77b643b9f8a24f1ee1c32132648b1c62ab93956f20fe101dde66db6d09a
+pytest-variables==1.9.0 \
+    --hash=sha256:ccf4afcd70de1f5f18b4463758a19f24647a9def1805f675e80db851c9e00ac0 \
+    --hash=sha256:f79851e4c92a94c93d3f1d02377b5ac97cc8800392e87d108d2cbfda774ecc2a
 pytest-base-url==1.4.1 \
     --hash=sha256:31e42366a5fc22f450b398837dc819bb7569f5e6bd5d74e494b2b9ec239876d1 \
     --hash=sha256:7425e8163345494ac7f544e99c6f3e5a08f4228bee5e26013b98c462a4d31f6e