Replace Travis w/ GH Actions

...

.github/workflows/swift.yml

@@ -0,0 +1,42 @@
+name: Build and Test
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: "0 9 * * 5"
+
+jobs:
+  linux:
+    runs-on: ubuntu-latest
+    if: github.ref != 'refs/heads/main'
+    strategy:
+      fail-fast: false
+      matrix:
+        image:
+          - swift:5.5.3-xenial
+          - swift:5.6.1-bionic
+          - swift:5.7.2-focal
+          - swift:5.8-jammy
+    container: ${{ matrix.image }}
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v3
+      - name: Build Swift Debug Package
+        run: swift build -c debug
+      - name: Build Swift Release Package
+        run: swift build -c release
+  nextstep:
+    runs-on: macos-latest
+    if: github.ref != 'refs/heads/main'
+    steps:
+      - name: Select latest available Xcode
+        uses: maxim-lobanov/[email protected]
+        with:
+          xcode-version: latest
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+      - name: Build Swift Debug Package
+        run: swift build -c debug
+      - name: Build Swift Release Package
+        run: swift build -c release