add validation CI

Author: gbkomoju

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: Validate
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  validate:
+    runs-on: [self-hosted, spot]
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2'
+      - name: Build gem
+        run: gem build komoju-sdk.gemspec