Use another mirror for boost

requirements.txt

 nlohmann/json
 https://gitlab.matrix.org/matrix-org/olm/-/archive/3.2.1/olm-3.2.1.zip -DBUILD_SHARED_LIBS=OFF
 gabime/spdlog -DSPDLOG_BUILD_BENCH=OFF -DSPDLOG_BUILD_EXAMPLES=OFF -DSPDLOG_BUILD_TESTS=OFF
-boost,https://kumisystems.dl.sourceforge.net/project/boost/boost/1.72.0/boost_1_72_0.tar.bz2 --cmake boost -DBUILD_SHARED_LIBS=OFF -DBOOST_WITH_IOSTREAMS=1 -DBOOST_WITH_SYSTEM=1 -DBOOST_WITH_THREAD=1 -DBOOST_WITH_HEADERS=1
+boost,https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76_0.tar.gz --cmake boost -DBUILD_SHARED_LIBS=OFF -DBOOST_WITH_IOSTREAMS=1 -DBOOST_WITH_SYSTEM=1 -DBOOST_WITH_THREAD=1 -DBOOST_WITH_HEADERS=1
 Nheko-Reborn/mtxclient@v0.5.1 -DBUILD_LIB_EXAMPLES=off -DBUILD_LIB_TESTS=OFF -DBUILD_SHARED_LIBS=OFF -DBoost_USE_STATIC_LIBS=ON