Added action to build documentation and json schema for validation (#2)

Co-authored-by: Pierre-Anthony Lemieux <[email protected]>

Author: reinecke

.github/workflows/build-specification.yml

@@ -0,0 +1,33 @@
+name: OpenTimelineIO-Specification
+
+on:
+  push:
+    branches: [ 'main' ]
+  pull_request:
+    branches: [ 'main' ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - run: sudo apt-get install graphviz
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '10'
+    - run: |
+        npm install
+        npm run build
+    - uses: actions/upload-artifact@v2
+      with:
+        name: documentation
+        path: |
+          build/
+          !build/otio.schema.json
+    - uses: actions/upload-artifact@v2
+      with:
+        name: json-schmea
+        path: build/otio.schema.json