Fix deprecation warnings for Chrome drivers

[dan-jensen]

Since PR #45, a warning is being output to console when using selenium-webdriver 4+:
:options as a parameter for driver initialization is deprecated. This
implements the :capabilities array as instructed, and makes a
requirement of selenium-webdriver 4+ because 3 does not support the
capabilities syntax.

Related links:

• Related capybara issue
• Helpful StackOverflow post

Using the capabilities syntax with selenium-webdriver 3.x (for example 3.142.7, the latest 3.x) raises an exception:

ArgumentError:
  unknown option: {:capabilities=>[#<Selenium::WebDriver::Chrome::Options:0x00007ffc4c0a2df0 @args=#<Set: {"--no-sandbox", "--headless"}>, @binary=nil, @prefs={}, @extensions=[], @options={}, @emulation={}, @detach=nil, @profile=nil, @encoded_extensions=[]>]}

[dan-jensen]

@dillonhafer this is a follow-up to PR #45, to eliminate the deprecation warning that appears when using selenium-webdriver 4.x.