vendor: update cpp-httplib version (#19313) #34

Job	Run time
ubuntu-22-vulkan	35s
macOS-arm64	23s
windows (vulkan, x64, -DGGML_VULKAN=ON, ggml-vulkan)	26s
ios-xcode-build	40s
windows-cpu (arm64)	1s
windows-sycl	1s
windows (opencl-adreno, arm64, -G "Ninja Multi-Config" -D CMAKE_TOOLCHAIN_FILE=cmake/arm64-window...	1s
windows-cuda (12.4)	26s
ubuntu-22-cpu (s390x, ubuntu-24.04-s390x)	23s
windows-hip (radeon, gfx1151;gfx1200;gfx1201;gfx1100;gfx1101;gfx1102;gfx1030;gfx1031;gfx1032)	24s
windows-cpu (x64)	1s
windows-cuda (13.1)	1s
openEuler-cann (aarch64, 310p, Release, off)	1s
ubuntu-22-cpu (x64, ubuntu-22.04)	1s
openEuler-cann (x86, 910b, Release, on)	2s
openEuler-cann (aarch64, 910b, Release, on)	23s
macOS-x64	23s
openEuler-cann (x86, 310p, Release, off)	1s
release	1s
	4m 14s

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