Update README & CI pipeline

Summary: related to T12804

Reviewers: ivica

Reviewed By: ivica

Subscribers: miljen, iljazovic

Differential Revision: https://repo.mireo.local/D27469

.github/workflows/ci.yml

@@ -127,6 +127,16 @@ jobs:
             cxxflags: ''
             ldflags: ''
 
+          - toolset: g++-12
+            compiler: g++-12
+            install: g++-12
+            os: ubuntu-latest
+            container: ubuntu:22.04
+            build-type: 'Release'
+            cxxstd: 20
+            cxxflags: ''
+            ldflags: ''
+
           - toolset: clang++-12
             compiler: clang++-12
             install: clang++-12
@@ -137,6 +147,16 @@ jobs:
             cxxflags: '-fdeclspec'
             ldflags: ''
 
+          - toolset: clang++-13
+            compiler: clang++-13
+            install: clang++-13
+            os: ubuntu-latest
+            container: ubuntu:22.04
+            build-type: 'Release'
+            cxxstd: 17
+            cxxflags: '-fdeclspec'
+            ldflags: ''
+
           - toolset: clang++-14-libc++-14
             compiler: clang++-14
             install: 'clang++-14 libc++-14-dev libc++abi-14-dev'