Maturity date bump for Web IDE

Why is this change being made?

Web IDE maturity is expected to be Complete following the transition to VS Code, but the CMS is in progress and won't likely be wrapped up and analyzed by the June 22 date. Bumping this out one month to give us time to run the scorecard and validate the maturity.

See Web IDE Category Maturity Scorecard (gitlab-org/gitlab#410616 - closed)

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