docs: update EOL table for 5.x versions

[vigneshshanmugam]

Update the https://www.elastic.co/guide/en/apm/agent/rum-js/master/upgrading.html#end-of-life-dates End of life dates for all 5.x versions - https://www.elastic.co/guide/en/apm/agent/rum-js/master/release-notes-5.x.html

/cc @bmorelli25

[andresrc]

would this be part of https://github.com/elastic/observability-docs/issues/919 ?

[bmorelli25]

~They are similar but not the same. This issue is related to conversations occurring in https://github.com/elastic/observability-robots/discussions/689.~

Edit #1 ~After reading some more, yes, I think this is considered a part of that other issue.~

Edit #2 @vigneshshanmugam we discussed this issue in our 7.15 planning meeting today. Like Trent points out in https://github.com/elastic/observability-robots/discussions/689#discussioncomment-1038729, each agent is taking a different approach to EOL table maintenance. We think it makes more sense for agent devs to keep these up to date, so we haven't prioritized this issue for 7.15.