CI: remove default Ubuntu build from GitHub Actions

We are already running a very similar Ubuntu build on Travis CI.
The macOS variant of this default build is kept on Github Actions.

diff --git a/.github/workflows/cpp.yml b/.github/workflows/cpp.yml
deleted file mode 100644 (file)
index 94eb070..0000000
--- a/.github/workflows/cpp.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-name: Build on Ubuntu with default options
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-    
-    steps:
-    - uses: actions/checkout@v1
-    - name: configure
-      run: ./buildconf && ./configure
-    - name: make
-      run: make
-    - name: make check
-      run: make test-nonflaky