Exiv2: download ældre versioner

What's Changed
- Fix leak by @kevinbackhouse in #3464
- CI: update mac runner for 0.28.x branch by @kmilos in #3470
- Add some new cameras and lenses (backport #3450) by @kmilos in #3466
- Make DataValue::value_ public (backport #3392) by @mergify[bot] in #3474
- fix reading mp4 url box nested in non video/audio track (#3425) (backport #3426) by @mergify[bot] in #3472
- fix: do not add target exiv2lib if the target already exists (backport #3435) by @mergify[bot] in #3473
- Add size checks to avoid large memory allocations (backport #3457) by @mergify[bot] in #3475
- Fix size calculation in XmpTextValue::size() (backport #3458) by @mergify[bot] in #3463
- Avoid calling std::find or std::string with an invalid range (backport #3469) by @mergify[bot] in #3478
- Backport all changes in .github/workflows from main to 0.28.x by @kevinbackhouse in #3480
- Fix out-of-bounds read in CrwMap::decode0x0805 by @kevinbackhouse in #3462
- Fix UBSAN false positive (backport #3483) by @mergify[bot] in #3485
- Upload crash files when fuzzing fails (backport #3482) by @mergify[bot] in #3487
- Remove nightly release (backport #3479) by @mergify[bot] in #3488
- Fix regression in Canon lens detection (backport #1421) by @kmilos in #3489
- fix wrong timescale used to calculate fps (backport #3437) by @mergify[bot] in #3491
- Remove nightly release vestiges (backport #3492) by @mergify[bot] in #3494
- conan: update dependencies by @kmilos in #3498
- Add Tamron 18-400mm on Nikon D90 (backport #3495) by @mergify[bot] in #3499
- Add Ricoh GR IV HDF and Monochrome IDs by @kmilos in #3500
- Refresh translations by @kmilos in #3503
- Add build provenance attestation (backport #3504) by @mergify[bot] in #3506
- Add fuzz target for previews (backport #3505) by @mergify[bot] in #3507
- Align some docs to main by @kmilos in #3508
- Update README.md by @kmilos in #3510
- add enforce to prevent integer overflow (backport #3512) by @mergify[bot] in #3516
- Add enforce to check for integer overflow (backport #3514) by @mergify[bot] in #3517
- Release Exiv2 version 0.28.8 by @kevinbackhouse in #3493
Full Changelog: v0.28.7...v0.28.8