expat: Update to version 2.7.1

expat: Update to version 2.7.1

- Update from version 2.7.0 to 2.7.1
- Update of rootfile
- Changelog
    2.7.1
        Bug fixes:
	       #980 #989  Restore event pointer behavior from Expat 2.6.4
                    (that the fix to CVE-2024-8176 changed in 2.7.0);
                    affected API functions are:
                    - XML_GetCurrentByteCount
                    - XML_GetCurrentByteIndex
                    - XML_GetCurrentColumnNumber
                    - XML_GetCurrentLineNumber
                    - XML_GetInputContext
        Other changes:
	       #976 #977  Autotools: Integrate files "fuzz/xml_lpm_fuzzer.{cpp,proto}"
	                    with Automake that were missing from 2.7.0 release tarballs
	       #983 #984  Fix printf format specifiers for 32bit Emscripten
	            #992  docs: Promote OpenSSF Best Practices self-certification
	            #978  tests/benchmark: Resolve mistaken double close
	            #986  Address compiler warnings
	       #990 #993  Version info bumped from 11:1:10 (libexpat*.so.1.10.1)
	                    to 11:2:10 (libexpat*.so.1.10.2); see https://verbump.de/
	                    for what these numbers do
        Infrastructure:
	            #982  CI: Start running Perl XML::Parser integration tests
	            #987  CI: Enforce Clang Static Analyzer clean code
	            #991  CI: Re-enable warning clang-analyzer-valist.Uninitialized
	                    for clang-tidy
	            #981  CI: Cover compilation with musl
	       #983 #984  CI: Cover compilation with 32bit Emscripten
	       #976 #977  CI: Protect against fuzzer files missing from future
	                    release archives

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>