Add 'Notify Owners' workflow

Author: moz-mdauer

.github/owners.json

@@ -0,0 +1,3 @@
+{
+  "nss": ["@dennisjackson"]
+}

.github/scripts/owners.js

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+module.exports = async ({ github, context, core }) => {
+  const path = require("path");
+  const owners = require(
+    path.join(process.env.GITHUB_WORKSPACE, ".github", "owners.json"),
+  );
+
+  const pullNumber = context.payload.pull_request?.number;
+  const listFiles = await github.rest.pulls.listFiles({
+    owner: context.repo.owner,
+    repo: context.repo.repo,
+    pull_number: pullNumber,
+  });
+
+  const modifiedModules = new Set();
+  for (const file of listFiles.data) {
+    const filename = file.filename;
+    if (filename.startsWith("modules/")) {
+      modifiedModules.add(filename.split("/")[1]);
+    }
+  }
+
+  if (modifiedModules.size === 0) {
+    core.info("No modules were modified");
+    return;
+  }
+
+  const commentParts = [
+    "<!-- owners-notification-bot -->",
+    "A review is required from the following owners:",
+  ];
+  for (const modifiedModule of modifiedModules) {
+    if (owners[modifiedModule]) {
+      commentParts.push(
+        `- ${modifiedModule}: ${owners[modifiedModule].join(", ")}`,
+      );
+    }
+  }
+
+  if (commentParts.length === 2) {
+    core.info("Modules were modified, but no owners were found");
+    return;
+  }
+
+  const listComments = await github.rest.issues.listComments({
+    owner: context.repo.owner,
+    repo: context.repo.repo,
+    issue_number: pullNumber,
+  });
+  const comment = listComments.data.find(
+    (comment) =>
+      comment.user.login === "github-actions[bot]" &&
+      comment.body.startsWith(commentParts[0]),
+  );
+  if (comment) {
+    core.info("Updating existing comment");
+    await github.rest.issues.updateComment({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      comment_id: comment.id,
+      body: commentParts.join("\n"),
+    });
+  } else {
+    core.info("Creating new comment");
+    await github.rest.issues.createComment({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      issue_number: pullNumber,
+      body: commentParts.join("\n"),
+    });
+  }
+};

.github/workflows/owners.yml

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+name: Notify Owners
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+permissions:
+  pull-requests: write
+  contents: read
+
+jobs:
+  notify-owners:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Notify Owners
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const script = require('./.github/scripts/owners.js');
+            await script({ github, context, core });