chore: Migrate from CircleCI to GitHub Actions

Author: keelerm84

.circleci/config.yml

@@ -0,0 +1,59 @@
+name: Quality control
+on:
+  push:
+    branches: [main, 'feat/**']
+    paths-ignore:
+      - '**.md' # Do not need to run CI for markdown changes.
+  pull_request:
+    branches: [main, 'feat/**']
+    paths-ignore:
+      - '**.md'
+
+jobs:
+  build-and-test:
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            version: 3.1
+            build-frameworks: netcoreapp3.1
+            test-framework: netcoreapp3.1
+          - os: ubuntu-latest
+            version: 6.0
+            build-frameworks: net6.0
+            test-framework: net6.0
+          - os: windows-latest
+            version: 4.6.2
+            build-frameworks: net462
+            test-framework: net462
+      fail-fast: false
+
+    runs-on: ${{ matrix.os }}
+
+    env:
+      DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=1
+      ASPNETCORE_SUPPRESSSTATUSMESSAGES: true
+      BUILDFRAMEWORKS: ${{ matrix.build-frameworks }}
+      TESTFRAMEWORK: ${{ matrix.test-framework }}
+
+    permissions:
+      id-token: write
+      contents: read
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup dotnet build tools
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: ${{ matrix.version }}
+
+      - name: Restore Dependencies
+        run: dotnet restore
+
+      - name: Build
+        shell: bash
+        run: dotnet build
+
+      - name: Run Unit Tests
+        run: dotnet test

.github/workflows/ci.yml

@@ -1,7 +1,7 @@
 # LaunchDarkly .NET Test Helpers
 
 [![NuGet](https://img.shields.io/nuget/v/LaunchDarkly.TestHelpers.svg?style=flat-square)](https://www.nuget.org/packages/LaunchDarkly.TestHelpers/)
-[![CircleCI](https://circleci.com/gh/launchdarkly/dotnet-test-helpers.svg?style=shield)](https://circleci.com/gh/launchdarkly/dotnet-test-helpers)
+[![Quality control](https://github.com/launchdarkly/dotnet-test-helpers/actions/workflows/ci.yml/badge.svg)](https://github.com/launchdarkly/dotnet-test-helpers/actions/workflows/ci.yml)
 [![Documentation](https://img.shields.io/static/v1?label=GitHub+Pages&message=API+reference&color=00add8)](https://launchdarkly.github.io/dotnet-test-helpers)
 
 This project centralizes some test support code that is used by LaunchDarkly's .NET and Xamarin SDKs and related components, and that may be useful in other .NET projects.