ci: bump absl dependency [backport 1.20] (#7899)

Backport 14e5b24 from #7895 to 1.20.

In order to fix alpine compilation issue:

https://github.com/DataDog/dd-trace-py/actions/runs/7179979155/job/19551323413?pr=7892

Upstream fix in abseil:

abseil/abseil-cpp@4500c2f

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [x] Title is accurate.
- [x] No unnecessary changes are introduced.
- [x] Description motivates each change.
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Testing strategy adequately addresses listed risk(s).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] Release note makes sense to a user of the library.
- [x] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [x] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [x] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [x] This PR doesn't touch any of that.

Co-authored-by: Federico Mon <[email protected]>

Author: avara1986

ddtrace/appsec/iast/_taint_tracking/CMakeLists.txt

@@ -22,9 +22,10 @@ else()
 endif(BUILD_MACOS)
 unset(BUILD_MACOS CACHE)
 
+
 FetchContent_Declare(
         absl
-        URL "https://github.com/abseil/abseil-cpp/archive/refs/tags/20211102.0.zip"
+        URL "https://github.com/abseil/abseil-cpp/archive/refs/tags/20230802.1.zip"
 )
 FetchContent_MakeAvailable(absl)