Update "tested on" badge in README to include PHP v8.3 #701

Job	Run time
Lint: PHP 5.4	24s
Lint: PHP 7.0	13s
Lint: PHP 7.4	14s
Lint: PHP 8.0	19s
Lint: PHP 8.3	33s
Lint: PHP 8.4	32s
Test: PHP 5.5 - PHPCS lowest	34s
Test: PHP 5.5 - PHPCS dev-master	32s
Test: PHP 5.6 - PHPCS lowest	30s
Test: PHP 5.6 - PHPCS dev-master	22s
Test: PHP 7.0 - PHPCS lowest	23s
Test: PHP 7.0 - PHPCS dev-master	22s
Test: PHP 7.1 - PHPCS lowest	19s
Test: PHP 7.1 - PHPCS dev-master	17s
Test: PHP 7.2 - PHPCS lowest	24s
Test: PHP 7.2 - PHPCS dev-master	17s
Test: PHP 7.3 - PHPCS lowest	18s
Test: PHP 7.3 - PHPCS dev-master	16s
Test: PHP 7.4 - PHPCS lowest	17s
Test: PHP 7.4 - PHPCS dev-master	16s
Test: PHP 8.0 - PHPCS lowest	24s
Test: PHP 8.0 - PHPCS dev-master	15s
Test: PHP 8.1 - PHPCS lowest	19s
Test: PHP 8.1 - PHPCS dev-master	15s
Test: PHP 8.2 - PHPCS lowest	20s
Test: PHP 8.2 - PHPCS dev-master	22s
Test: PHP 8.4 - PHPCS dev-master	35s
Test: PHP 7.4 - PHPCS 4.0.x-dev	15s
Test: PHP 7.4 - PHPCS 4.0.x-dev (risky)	13s
Test: PHP 5.4 - PHPCS lowest (risky)	25s
Test: PHP 5.4 - PHPCS dev-master (risky)	18s
Test: PHP 8.3 - PHPCS lowest (risky)	32s
Test: PHP 8.3 - PHPCS dev-master (risky)	37s
Coverage: PHP 8.3 - PHPCS dev-master	57s
Coverage: PHP 8.3 - PHPCS lowest	1m 0s
Coverage: PHP 5.4 - PHPCS dev-master	1m 23s
Coverage: PHP 5.4 - PHPCS lowest	1m 28s
coveralls-finish	3s
	17m 3s

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