Update integration authentication documentation for usage with lcobucci/jwt ^4

[glaubinix]

The security docs were mentioning lcobucci/jwt:^3.4 which doesn't support php 8. Updated the security docs to reflect all necessary changes to work with lcobucci/jwt:^4.1

Passing ChainedFormatter::withUnixTimestampDates() to the builder method is necessary because otherwise all dates will be format via $date->format('U.u') as microseconds. GitHub expects unix timestamps and will return a 401 response with 'Expiration time' claim ('exp') must be a numeric value representing the future time at which the assertion expires.

[raghavendra89]

Thanks! I just wanted to submit a pull request for this. But saw yours.

There is one more minor issue at line 48:
$github = new Github\Client($builder, 'machine-man-preview');

Here $builder variable is referenced, but it is not initiated. We can add this line before line 48:

$builder = new Builder(new GuzzleHttp\Client());

and include: use Github\HttpClient\Builder;

[acrobat]

@glaubinix can you apply the extra comments that @raghavendra89 made above? Thanks!

[glaubinix]

@acrobat done

[acrobat]

Thank you @glaubinix