(CI) boost graph v0.86 has fixes in functions we use

.github/workflows/boost_version.yml

@@ -19,6 +19,7 @@ name: Boost supported versions
 # - boost::geometry has not changed anything we use
 #
 # boost::graph
+# - 1.86 does not support C++11 (Aug 2024)
 # - 1.84 is failing its own tests (Jul 2022)
 # - 1.83 transitive closure & stoer wagner changed on 83 (Jul 2022)
 # - 1.80 changed on 1.80 (Aug 2022)
@@ -69,7 +70,7 @@ jobs:
     strategy:
         fail-fast: false
         matrix:
-          boost_minor: [56, 68, 75, 76, 77, 78, 79, 80, 83, 84]
+          boost_minor: [56, 68, 75, 76, 77, 78, 79, 80, 83, 84, 86]
 
     steps:
       - uses: actions/checkout@v4