Move code coverage to GitHub Actions (#176)

First step to move the build to GitHub Actions: move the coverage
generation from Travis to Actions. It doesn't generate additional
information with lcov anymore, and now always runs on the latest
available Ubuntu.

[ci skip]

.github/workflows/codecov.yml

@@ -0,0 +1,52 @@
+name: Coverage Upload to Codecov
+
+on:
+  push:
+    branches:
+      - coverage-action
+      - master
+      - develop
+      - 2.0.0-develop
+    paths:
+      - 'include/**'
+      - 'testsuite/**'
+
+env:
+  BUILD_TYPE: Debug
+
+jobs:
+  upload-coverage:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout project
+        uses: actions/checkout@v2
+
+      - name: Configure CMake
+        shell: bash
+        working-directory: ${{runner.workspace}}
+        run: >
+          cmake -H${{github.event.repository.name}} -Bbuild
+          -DCMAKE_BUILD_TYPE="${BUILD_TYPE}"
+          -DENABLE_COVERAGE=true
+          -G"Unix Makefiles"
+
+      - name: Build with coverage
+        shell: bash
+        working-directory: ${{runner.workspace}}/build
+        run: cmake --build . --config $BUILD_TYPE -j 2
+
+      - name: Run the test suite
+        shell: bash
+        working-directory: ${{runner.workspace}}/build
+        run: ctest -C Release --output-on-failure
+
+      - name: Create coverage info
+        shell: bash
+        working-directory: ${{runner.workspace}}/build
+        run: make gcov
+
+      - name: Upload coverage info
+        shell: bash
+        working-directory: ${{runner.workspace}}/build
+        run: bash <(curl -s https://codecov.io/bash) -X gcov || echo "Codecov did not collect coverage reports";

.travis.yml

@@ -146,19 +146,6 @@ matrix:
       env: BUILD_TYPE=Release CMAKE_GENERATOR="MinGW Makefiles"
       compiler: gcc
 
-    # Code coverage
-    - os: linux
-      sudo: false
-      if: branch in (master, develop)
-      env: BUILD_TYPE=Debug CMAKE_GENERATOR="Unix Makefiles" ENABLE_COVERAGE=true
-      addons:
-        apt:
-          <<: *apt-common
-          packages:
-            - *gcc
-            - lcov
-      compiler: gcc
-
 before_install:
   - if [[ $TRAVIS_OS_NAME = "linux" && $CXX = "clang++" ]]; then
         sudo ln -s $(which ccache) /usr/lib/ccache/clang++;
@@ -199,16 +186,6 @@ script:
         cd ..;
     fi
 
-after_success:
-  - if [[ $TRAVIS_OS_NAME = "windows" ]]; then
-        cd build;
-    fi
-  - if [[ $ENABLE_COVERAGE = true ]]; then
-        make gcov;
-        make lcov;
-        bash <(curl -s https://codecov.io/bash) -X gcov || echo "Codecov did not collect coverage reports";
-    fi
-
 after_failure:
   - if [[ $TRAVIS_OS_NAME = "windows" ]]; then
         cd build;