change source URL for boost

The old URL does not work, so this changes it to a yoctoproject url.
see https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/43405

Tested: The following error is not present after change
"could not get
http://dl.bintray.com/boostorg/release/1.71.0/source/boost_1_71_0.tar.gz
is the internet available?"

Signed-off-by: John Edward Broadbent <jebr@google.com>
Change-Id: Iddef20526c8b2fa1b083a71558a23712f21c21a2
diff --git a/subprojects/boost.wrap b/subprojects/boost.wrap
index 5448337..c6f6341 100644
--- a/subprojects/boost.wrap
+++ b/subprojects/boost.wrap
@@ -1,4 +1,4 @@
 [wrap-file]
-source_url = http://dl.bintray.com/boostorg/release/1.71.0/source/boost_1_71_0.tar.gz
-source_hash = 96b34f7468f26a141f6020efb813f1a2f3dfb9797ecf76a7d7cbd843cc95f5bd
-source_filename = boost_1_71_0.tar.gz
+source_url = https://downloads.yoctoproject.org/mirror/sources/boost_1_71_0.tar.bz2
+source_hash = d73a8da01e8bf8c7eda40b4c84915071a8c8a0df4a6734537ddde4a8580524ee
+source_filename = boost_1_71_0.tar.bz2