modernize CI setup

Author: apolukhin

.github/workflows/ci.yml

@@ -30,18 +30,6 @@ jobs:
             linkflags: "linkflags=--coverage -lasan -lubsan"
             launcher: "testing.launcher=LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libasan.so.6"
             gcov_tool: "gcov-10"
-          - toolset: clang
-            compiler: clang++-3.7
-            cxxstd: "03,11,14"
-            os: ubuntu-16.04
-            install: clang-3.7
-          - toolset: clang
-            compiler: clang++-9
-            cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-            cxxflags: "cxxflags=--coverage"
-            linkflags: "linkflags=--coverage"
-            gcov_tool: "llvm-cov-9 gcov"
           - toolset: clang
             compiler: clang++-10
             cxxstd: "03,11,14,17,2a"
@@ -87,11 +75,6 @@ jobs:
           ./b2 -d0 headers
           ./b2 -j4 variant=debug tools/inspect/build
 
-      - name: Create user-config.jam
-        if: matrix.compiler
-        run: |
-          echo "using ${{matrix.toolset}} : : ${{matrix.compiler}} ;" > ~/user-config.jam
-
       - name: Run tests
         run: |
           cd ../boost-root

.travis.yml

@@ -8,8 +8,8 @@ Boost.Stacktrace is a part of the [Boost C++ Libraries](https://github.com/boost
 ### Test results
 @               | Build         | Tests coverage | More info
 ----------------|-------------- | -------------- |-----------
-Develop branch:  | [![CI](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml) [![Build Status](https://travis-ci.org/boostorg/stacktrace.svg?branch=develop)](https://travis-ci.org/boostorg/stacktrace) [![Build status](https://ci.appveyor.com/api/projects/status/l3aak4j8k39rx08t/branch/develop?svg=true)](https://ci.appveyor.com/project/apolukhin/stacktrace/branch/develop) | [![Coverage Status](https://coveralls.io/repos/github/boostorg/stacktrace/badge.svg?branch=develop)](https://coveralls.io/github/boostorg/stacktrace?branch=develop) | [details...](https://www.boost.org/development/tests/develop/developer/stacktrace.html)
-Master branch:  | [![CI](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml) [![Build Status](https://travis-ci.org/boostorg/stacktrace.svg?branch=master)](https://travis-ci.org/boostorg/stacktrace) [![Build status](https://ci.appveyor.com/api/projects/status/l3aak4j8k39rx08t/branch/master?svg=true)](https://ci.appveyor.com/project/apolukhin/stacktrace/branch/master) | [![Coverage Status](https://coveralls.io/repos/github/boostorg/stacktrace/badge.svg?branch=master)](https://coveralls.io/github/boostorg/stacktrace?branch=master) | [details...](https://www.boost.org/development/tests/master/developer/stacktrace.html)
+Develop branch:  | [![CI](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml) [![Build status](https://ci.appveyor.com/api/projects/status/l3aak4j8k39rx08t/branch/develop?svg=true)](https://ci.appveyor.com/project/apolukhin/stacktrace/branch/develop) | [![Coverage Status](https://coveralls.io/repos/github/boostorg/stacktrace/badge.svg?branch=develop)](https://coveralls.io/github/boostorg/stacktrace?branch=develop) | [details...](https://www.boost.org/development/tests/develop/developer/stacktrace.html)
+Master branch:  | [![CI](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/stacktrace/actions/workflows/ci.yml) [![Build status](https://ci.appveyor.com/api/projects/status/l3aak4j8k39rx08t/branch/master?svg=true)](https://ci.appveyor.com/project/apolukhin/stacktrace/branch/master) | [![Coverage Status](https://coveralls.io/repos/github/boostorg/stacktrace/badge.svg?branch=master)](https://coveralls.io/github/boostorg/stacktrace?branch=master) | [details...](https://www.boost.org/development/tests/master/developer/stacktrace.html)
 
 [Latest developer documentation](https://www.boost.org/doc/libs/develop/doc/html/stacktrace.html)