add build yml

Signed-off-by: oppiliappan <[e-mail]>

.tangled/workflows/build.yml

···
+when:
+  - event: ["push", "pull_request"]
+    branch: ["main", "master", "develop"]
+
+dependencies:
+
+steps:
+  - name: "build"
+    command: |
+       nix build .#appview