Add Github Actions configuation

.github/workflows/build.yml

@@ -0,0 +1,23 @@
+name: CI
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: macOS-latest
+    
+    steps:
+    - name: Checkout Project
+      uses: actions/checkout@v1
+      with: 
+        submodules: recursive
+
+    - name: Switch to Xcode 11
+      run: sudo xcode-select -s /Applications/Xcode_11.app
+    
+    - name: Run Build
+      env:
+          ENCRYPTION_SECRET: ${{ secrets.ENCRYPTION_SECRET }}
+          KEY_SECRET: ${{ secrets.KEY_SECRET }}
+      run: buildscripts/ci-build.sh

buildscripts/ci-build.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+set -v
+set -e
+
+openssl aes-256-cbc -k "$ENCRYPTION_SECRET" -in buildscripts/certs/dev.cer.enc -d -a -out buildscripts/certs/dev.cer
+openssl aes-256-cbc -k "$ENCRYPTION_SECRET" -in buildscripts/certs/dev.p12.enc -d -a -out buildscripts/certs/dev.p12
+
+security create-keychain -p github-actions github-build.keychain
+security import buildscripts/certs/apple.cer -k ~/Library/Keychains/github-build.keychain -A
+security import buildscripts/certs/dev.cer -k ~/Library/Keychains/github-build.keychain -A
+security import buildscripts/certs/dev.p12 -k ~/Library/Keychains/github-build.keychain -P $KEY_SECRET -A
+security set-key-partition-list -S apple-tool:,apple: -s -k github-actions github-build.keychain
+security default-keychain -s github-build.keychain
+
+rm -f ./buildscripts/certs/dev.cer
+rm -f ./buildscripts/certs/dev.p12
+
+xcodebuild -scheme 'NetNewsWire' -configuration Release -allowProvisioningUpdates -showBuildTimingSummary
+
+security delete-keychain github-build.keychain