MDL-66979: Switch to php-webdriver/webdriver

This is currently using oleg-andreyev/MinkPhpWebDriver but I have raised
oleg-andreyev/MinkPhpWebDriver#4 to look at
moving the project to php-wbdriver/MinkPhpWebDriver and trying to push
it as the authoritative Mink driver.

Author: andrewnicols

Diff for: composer.json

@@ -17,10 +17,16 @@
         "behat/mink": "~1.8",
         "behat/mink-extension": "~2.3",
         "behat/mink-goutte-driver": "~1.2",
-        "behat/mink-selenium2-driver": "~1.4",
+        "oleg-andreyev/mink-facebook-web-driver": "dev-webdriver-1.8 as 1.8.x-dev",
         "symfony/process": "^4.0 || ^5.0",
         "behat/behat": "3.6.*"
-    },
+     },
+    "repositories": [
+        {
+            "type": "vcs",
+            "url": "https://github.com/oleg-andreyev/MinkPhpWebDriver"
+        }
+    ],
     "autoload": {
         "psr-0": {
             "Moodle\\BehatExtension": "src/"