Travis has been dead for years, so switch to GitHub actions

Author: TinoDidriksen

.github/workflows/build.yaml

@@ -0,0 +1,25 @@
+name: libdivvun CI Build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: dependencies
+      run: |
+           sudo apt-get -qy update
+           sudo apt-get -qfy install wget ca-certificates
+           wget -q https://apertium.projectjj.com/apt/install-nightly.sh -O - | sudo bash
+           sudo apt-get -qfy install --no-install-recommends autotools-dev gawk hfst-ospell-dev libarchive-dev libcg3-dev libhfst-dev libpugixml-dev libutfcpp-dev libxml2-utils pkg-config python3-dev python3-setuptools swig zip
+    - name: autoreconf
+      run: autoreconf -fvi
+    - name: configure
+      run: ./configure --enable-checker --enable-cgspell --enable-python-bindings
+    - name: build
+      run: make -j4 V=1 VERBOSE=1
+    - name: tests
+      run: make test V=1 VERBOSE=1
+    - name: make install
+      run: sudo make install