Include <algorithm> for std::transform

[ellert]

/builddir/build/BUILD/xrootd-s3-http-0.1.8-build/xrootd-s3-http-0.1.8/test/s3_unit_tests.cc: In member function ‘virtual void AmazonS3SendMultipartPartLowercase::modifyResponse(std::string&)’:
/builddir/build/BUILD/xrootd-s3-http-0.1.8-build/xrootd-s3-http-0.1.8/test/s3_unit_tests.cc:589:22: error: ‘transform’ is not a member of ‘std’
  589 |                 std::transform(resp.begin(), resp.end(), resp.begin(),
      |                      ^~~~~~~~~
gmake[2]: *** [test/CMakeFiles/s3-unit-test.dir/build.make:82: test/CMakeFiles/s3-unit-test.dir/s3_unit_tests.cc.o] Error 1
gmake[2]: Leaving directory '/builddir/build/BUILD/xrootd-s3-http-0.1.8-build/xrootd-s3-http-0.1.8/redhat-linux-build'
gmake[1]: *** [CMakeFiles/Makefile2:359: test/CMakeFiles/s3-unit-test.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....

[bbockelm]

LGTM.

[bbockelm]

Thanks @ellert!

What platform were you running that hit this issue? Your submission is obviously correct from a C++ point of view but this indicates a deficiency in our CI (which only hits ubuntu-24.04).

Brian