fix: auto-deploy testnet contracts with github actions

.github/workflows/deploy-contracts.yml

@@ -0,0 +1,32 @@
+name: deploy-contracts
+on:
+  schedule:
+    - cron: "*/15 * * * *"
+  workflow_dispatch:
+
+jobs:
+  deploy-contracts:
+    runs-on: ubuntu-latest
+    env:
+      API_SERVER: https://stacks-node-api.blockstack.org
+      CONTRACT_PRIVATE_KEY: ${{ secrets.CONTRACT_PRIVATE_KEY }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set Node Version
+        uses: actions/setup-node@v2-beta
+        with:
+          node-version: 12.16.1
+      - name: Restore lerna cache
+        id: lerna-cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            node_modules
+            */*/node_modules
+          key: ${{ runner.os }}-${{ hashFiles('**/yarn.lock') }}
+      - name: Install monorepo deps
+        run: yarn --frozen-lockfile
+        if: steps.lerna-cache.outputs.cache-hit != 'true'
+      - name: Deploy contracts
+        run: yarn deploy-contracts