Create release.yml (#14)

Author: mattt

.github/workflows/release.yml

@@ -0,0 +1,16 @@
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out
+        uses: actions/checkout@v3
+
+      - name: Publish to Hex.pm
+        uses: erlangpack/github-action@v3
+        env:
+          HEX_API_KEY: ${{ secrets.HEX_API_KEY }}