Update ubuntu.yml (boost link)

Author: vfisikop

.github/workflows/ubuntu.yml

@@ -29,7 +29,7 @@ jobs:
         git submodule update --init;
     - name: Download and unzip the boost library
       run: |
-        wget -O boost_1_76_0.tar.bz2 https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76_0.tar.bz2;
+        wget -O boost_1_76_0.tar.bz2 https://archives.boost.io/release/1.76.0/source/boost_1_76_0.tar.bz2;
         tar xjf boost_1_76_0.tar.bz2;
         rm boost_1_76_0.tar.bz2;
     - name: Download and unzip the lp-solve library