ci: setup github actions

.github/workflows/check.yml

@@ -0,0 +1,19 @@
+name: Checks (on Linux)
+
+on:
+  workflow_call:
+
+jobs:
+  lint:
+    name: Run linters and code checks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v25
+        with:
+          nix_path: nixpkgs=channel:nixos-23.11
+      - uses: cachix/cachix-action@v14
+        with:
+          name: apibara-public
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+      - run: nix flake check

.github/workflows/pipeline.yml

@@ -0,0 +1,15 @@
+name: CI Pipeline
+
+concurrency:
+  group: pipeline-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+on:
+  push:
+    branches:
+      - new-pipeline
+
+jobs:
+  check:
+    name: "Checks"
+    uses: ./.github/workflows/check.yml