Update ci.yml

Author: pdimov

.github/workflows/ci.yml

@@ -30,16 +30,19 @@ jobs:
             os: ubuntu-latest
             install: g++-6
           - toolset: gcc-7
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: g++-7
 # gcc-8 variant=release crashes
 #          - toolset: gcc-8
 #            os: ubuntu-20.04
 #            install: g++-8
           - toolset: gcc-9
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
           - toolset: gcc-10
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: g++-10
           - toolset: gcc-11
             os: ubuntu-22.04
@@ -72,31 +75,38 @@ jobs:
             install: clang-5.0
           - toolset: clang
             compiler: clang++-6.0
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-6.0
           - toolset: clang
             compiler: clang++-7
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-7
           - toolset: clang
             compiler: clang++-8
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-8
           - toolset: clang
             compiler: clang++-9
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-9
           - toolset: clang
             compiler: clang++-10
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-10
           - toolset: clang
             compiler: clang++-11
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-11
           - toolset: clang
             compiler: clang++-12
-            os: ubuntu-20.04
+            container: ubuntu:20.04
+            os: ubuntu-latest
             install: clang-12
           - toolset: clang
             compiler: clang++-13