Create linuxbuild.yml

See if we can build release binaries.

.github/workflows/linuxbuild.yml

@@ -0,0 +1,14 @@
+name: linuxbuild
+
+on:
+  release:
+    types:
+      - created
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: make
+      run: make