ci: add workflow triggered by merge to main (#37)

Release-As: 1.0.1

.github/workflows/on-push-main.yaml

@@ -0,0 +1,31 @@
+name: Push to main
+on:
+  push:
+    branches: [main]
+
+jobs:
+  snyk:
+    name: Scan dependencies
+    uses: ./.github/workflows/snyk.yaml
+    with:
+      severity-treshold: low
+    secrets: inherit
+    permissions:
+      contents: read
+      security-events: write
+
+  semgrep:
+    name: Scan source code
+    uses: ./.github/workflows/semgrep.yaml
+    secrets: inherit
+    permissions:
+      contents: read
+      security-events: write
+
+  release-please:
+    name: Create release-please PR
+    uses: ./.github/workflows/release-please.yaml
+    secrets: inherit
+    permissions:
+      contents: write
+      pull-requests: write