ci: Push on main branch only

Author: kkrypt0nn

.github/workflows/ci.yml

@@ -1,9 +1,9 @@
 name: AoC CI (Lint & Test)
 
-on: [ push, pull_request ]
-
-permissions:
-  contents: read
+on:
+  push:
+    branches:
+      - main
 
 jobs:
   lint:
@@ -19,20 +19,7 @@ jobs:
         uses: golangci/golangci-lint-action@v3
         with:
           version: latest
-  test:
-    name: Test
-    needs: lint
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        version: [ "1.18.0", "1.19.0", "1.20.0", "1.21.0", "stable" ]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Go
-        uses: actions/setup-go@v4
-        with:
-          go-version: ${{matrix.version}}
       - name: Build
         run: go build -v ./...
       - name: Test
-        run: go test -v ./...
+        run: go test -v ./...