Maintenance: Bump selenium-webdriver from 3.142.7 to 4.0.0

Bumps [selenium-webdriver](https://github.com/SeleniumHQ/selenium) from 3.142.7 to 4.0.0.
- [Release notes](https://github.com/SeleniumHQ/selenium/releases)
- [Changelog](https://github.com/SeleniumHQ/selenium/blob/trunk/rb/CHANGES)
- [Commits](https://github.com/SeleniumHQ/selenium/commits/selenium-4.0.0)

Gemfile.lock

@@ -134,7 +134,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
-    childprocess (3.0.0)
+    childprocess (4.1.0)
     chunky_png (1.4.0)
     clavius (1.0.4)
     clearbit (0.3.3)
@@ -545,8 +545,9 @@ GEM
     sawyer (0.8.2)
       addressable (>= 2.3.5)
       faraday (> 0.8, < 2.0)
-    selenium-webdriver (3.142.7)
-      childprocess (>= 0.5, < 4.0)
+    selenium-webdriver (4.0.0)
+      childprocess (>= 0.5, < 5.0)
+      rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2)
     shellany (0.0.1)
     shoulda-matchers (5.0.0)