(#19) Add action to build project

This adds a new GitHub workflow file to be able to build the project
when a PR or a community member pushes up changes.

This is to give a quicker indication on failures than having to look at
our private builds (or a community member needing to reach out to a
Chocolatey Team Member to check).

The artifacts from the build (the extension/packages) themself are not
included with this build as they won't be able to be ran on any systems.
Only the unit tests can be ran as part of this workflow.

.github/workflows/build.yml

@@ -0,0 +1,37 @@
+name: Chocolatey Community Validation Builds
+
+on:
+  # Trigger on pushes and pull requests
+  push:
+  pull_request:
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  # Build on Windows
+  windows-build:
+    runs-on: windows-2019
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Cache Tools
+        uses: actions/cache@v3.0.11
+        with:
+          path: tools
+          key: ${{ runner.os }}-tools-${{ hashFiles('recipe.cake') }}
+      - name: Build with .NET Framework
+        run: ./build.ps1 --verbosity=diagnostic --target=CI --testExecutionType=unit --shouldRunOpenCover=false
+      - name: Upload Windows build results
+        uses: actions/upload-artifact@v3
+        if: ${{ always() }}
+        with:
+          name: windows-build-results
+          path: |
+            code_drop\TestResults\issues-report.html
+            code_drop\TestResults\NUnit\TestResult.xml
+            code_drop\TestCoverage\lcov.info
+            code_drop\TestCoverage\OpenCover.xml
+            code_drop\MsBuild.log
+# TODO: Add step to upload codecov results?