Add workflows and fix linter errors

.github/workflows/go-test-build.yaml

@@ -0,0 +1,20 @@
+name: go-test-build
+on:
+  push:
+  pull_request:
+
+jobs:
+  go-test-build:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/catthehacker/ubuntu:runner-latest
+    strategy:
+      matrix:
+        go: [ "1.22", "1.21" ]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go }}
+      - run: go test -v ./...
+      - run: go build -o main main.go

.github/workflows/golangci-lint.yaml

@@ -0,0 +1,19 @@
+name: golangci-lint
+on:
+  push:
+  pull_request:
+
+jobs:
+  goglangci-lint:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/catthehacker/ubuntu:runner-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.22"
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v6
+        with:
+          version: v1.61

.github/workflows/nix-check-build.yaml

@@ -0,0 +1,15 @@
+name: nix-check-build
+on:
+  push:
+  pull_request:
+
+jobs:
+  nix-check-build:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/catthehacker/ubuntu:runner-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v27
+      - run: nix flake check
+      - run: nix build