Merge pull request #129 from boostorg/CI

Replace deprecated OS with containers

Author: mborland

.github/workflows/ci.yml

@@ -70,19 +70,22 @@ jobs:
           - toolset: gcc-9
             cxxstd: "11,14,17,2a"
             address_model: 32,64
-            os: ubuntu-20.04
+            os: ubuntu-latest
+            container: ubuntu:20.04
             install:
               - g++-9-multilib
           - toolset: gcc-9
             cxxstd: "11-gnu,14-gnu,17-gnu,2a-gnu"
             address_model: 32,64
-            os: ubuntu-20.04
+            os: ubuntu-latest
+            container: ubuntu:20.04
             install:
               - g++-9-multilib
           - toolset: gcc-10
             cxxstd: "11,14,17,20"
             address_model: 32,64
-            os: ubuntu-20.04
+            os: ubuntu-latest
+            container: ubuntu:20.04
             install:
               - g++-10-multilib
           - toolset: gcc-11
@@ -167,13 +170,15 @@ jobs:
           - toolset: clang
             compiler: clang++-9
             cxxstd: "11,14,17,2a"
-            os: ubuntu-20.04
+            os: ubuntu-latest
+            container: ubuntu:20.04
             install:
               - clang-9
           - toolset: clang
             compiler: clang++-10
             cxxstd: "11,14,17,20"
-            os: ubuntu-20.04
+            os: ubuntu-latest
+            container: ubuntu:20.04
             install:
               - clang-10
           - toolset: clang
@@ -505,8 +510,8 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: ubuntu-20.04
           - os: ubuntu-22.04
+          - os: ubuntu-24.04
           - os: macos-13
           - os: macos-14