Fixed frame switching by name on Selenium 3

[aik099]

Fixes this error from the #383:

Behat\Mink\Tests\Driver\Basic\IFrameTest::testIFrame
WebDriver\Exception\InvalidArgument: data did not match any variant of untagged enum FrameId at line 3 column 1
Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:25:53'
System info: host: 'fv-az779-213', ip: '10.1.0.12', os.name: 'Linux', os.arch: 'amd64', os.version: '5.15.0-1056-azure', java.version: '1.8.0_[29](https://github.com/minkphp/MinkSelenium2Driver/actions/runs/8015977437/job/21897049622?pr=383#step:8:30)2'
Driver info: driver.version: unknown

Implementation ported from the https://github.com/minkphp/webdriver-classic-driver.

It appears, that on Selenium 3 frame switching is possible only by index or WebElement. This PR implements the later approach. In Selenium 2 frame switching by its name/id was also supported.

Additionally, the build script was updated to run tests on Selenium 3 in addition to Selenium 2. Should I split the build script change into a separate PR?

[codecov]

Codecov Report

Attention: Patch coverage is 82.35294% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 89.87%. Comparing base (4ca4083) to head (900ba20).

Files	Patch %	Lines
src/Selenium2Driver.php	82.35%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #382      +/-   ##
============================================
- Coverage     90.19%   89.87%   -0.32%     
- Complexity      168      174       +6     
============================================
  Files             1        1              
  Lines           469      484      +15     
============================================
+ Hits            423      435      +12     
- Misses           46       49       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[stof]

I suggest splitting the usage of Selenium 3 in CI into a separate PR as this is failing in CI (and maybe not worth the trouble given we have our new driver that aims at supporting it better)

[aik099]

@stof , extract build changes into #383 .

[aik099]

I've also created a PR instaclick/php-webdriver#132 to allow WebDriver to properly convert WebElement into JSON (as it should be doing initially). When it's merged + release is made that would allow me to remove that ugly WebElement wrapping code, that surely doesn't belong to this repo at all.

[aik099]

@stof , please review. Ideally please review my other PRs as well: https://github.com/minkphp/MinkSelenium2Driver/pulls/aik099 .