Add PCRE2_jll and Zlib_jll as known stdlibs

[eschnett]

Revise's list of stdlibs is incomplete. This is currently a blocker for JuliaLang/julia#58731: This PR updates LibGit2_jll to a new version, and this version has both PCRE2_jll and Zlib_jll as dependencies. Revise does not know about these two stdlibs, and this makes Julia's CI self tests fail.

This is a pared-down version of #929. That other PR still may or may not make sense.

After this PR is merged we will need to update the version of Revise used by Julia's CI tests.

[eschnett]

The build error on Windows looks like a spurious problem. Can you restart that build?

[eschnett]

The error on Windows with Julia 1.12-beta4 seems real. It looks as if this was a failure during garbage collection.

[eschnett]

The current build failures are not caused by this PR. I changed the PR to make no meaningful change (it only introduces a comment) and yet both one of the CI Windows builds and the CI documentation builds are failing. It might be that there is some incompatibility between Julia 1.12-beta4 and Revise on Windows.

How do you want to address this? I do not have a Windows machine to track down the problem (and it's independent of this PR). Would it be possible to merge this PR even while one of the Windows builds is failing? Or do you plan to fix this first?

[pfitzseb]

Seems like a good idea to merge this anyways and debug the Windows failure elsewhere.