add jl_test workflow

to run the Julia `] test`
on multiple Julia versions.

Author: etpinard

.github/workflows/jl_test.yml

@@ -0,0 +1,20 @@
+name: Run Julia tests
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        jl_version: ["1.3", "1.6", "1.8"]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.jl_version }}
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1
+        with:
+          annotate: true