Fetch expat from github because the project switched

Author: dns2utf8

Diff for: src/ci/docker/host-x86_64/dist-riscv64-linux/riscv64-unknown-linux-gnu.config

@@ -645,7 +645,8 @@ CT_EXPAT_PATCH_ORDER="global"
 CT_EXPAT_V_2_2=y
 # CT_EXPAT_NO_VERSIONS is not set
 CT_EXPAT_VERSION="2.4.1"
-CT_EXPAT_MIRRORS="https://downloads.sourceforge.net/project/expat/expat/${CT_EXPAT_VERSION}"
+CT_EXPAT_VERSION_TAG="2_4_1"
+CT_EXPAT_MIRRORS="https://github.com/libexpat/libexpat/releases/download/R_${CT_EXPAT_VERSION_TAG}"
 CT_EXPAT_ARCHIVE_FILENAME="@{pkg_name}-@{version}"
 CT_EXPAT_ARCHIVE_DIRNAME="@{pkg_name}-@{version}"
 CT_EXPAT_ARCHIVE_FORMATS=".tar.bz2"