More automatic deployment (#593)

<!-- The PR description should answer 2 (maybe 3) important questions:
-->

### What

We'd like to start automating the deployment of `ndc-postgres` and
friends, which means we need to introduce some scripts to GitHub
actions. However, it looks like we need to merge at least this
boilerplate in order to start playing with these actions in branches.

### How

<!-- How is it trying to accomplish it (what are the implementation
steps)? -->

.github/workflows/deploy.yaml

@@ -0,0 +1,21 @@
+on:
+  workflow_dispatch:
+    inputs:
+      new_version:
+        description: "What we want the new version to be"
+        required: true
+
+name: Deploy process
+
+jobs:
+  deploy:
+    name: cargo audit
+    runs-on: ubuntu-latest
+    env:
+      CARGO_NET_GIT_FETCH_WITH_CLI: "true"
+    steps:
+      - uses: actions/checkout@v4
+
+      - run: ./scripts/new-version.sh ${{ github.event.inputs.new_version }}
+
+      - run: cat Cargo.toml