[looker] Add release automation (#161)

Fetch Looker versions with their dates from the Google Cloud release notes RSS feed: https://cloud.google.com/feeds/looker-release-notes.xml.

Only version above 23.0 are retrieved, as prior version were not announced in the Google Cloud release notes.

src/looker.py

@@ -0,0 +1,42 @@
+import re
+
+from bs4 import BeautifulSoup
+from common import endoflife
+from datetime import datetime, timezone
+from xml.dom.minidom import parseString
+
+"""Fetch Looker versions with their dates from the Google Cloud release notes RSS feed.
+"""
+
+PRODUCT = "looker"
+URL = "https://cloud.google.com/feeds/looker-release-notes.xml"
+ANNOUNCEMENT_PATTERN = re.compile(r"includes\s+the\s+following\s+changes", re.IGNORECASE)
+VERSION_PATTERN = re.compile(r"Looker\s+(?P<version>\d+\.\d+)", re.IGNORECASE)
+
+
+def parse_date(date_str):
+    return datetime.fromisoformat(date_str).astimezone(timezone.utc).strftime("%Y-%m-%d")
+
+print(f"::group::{PRODUCT}")
+versions = {}
+
+response = endoflife.fetch_url(URL)
+rss = parseString(response)
+for item in rss.getElementsByTagName("entry"):
+    date = parse_date(item.getElementsByTagName("updated")[0].firstChild.nodeValue)
+    content = item.getElementsByTagName("content")[0].firstChild.nodeValue
+    soup = BeautifulSoup(content, features="html5lib")
+
+    announcement = soup.find(string=ANNOUNCEMENT_PATTERN)
+    if announcement:
+        m = re.search(VERSION_PATTERN, announcement.parent.get_text())
+        if m:
+            version = m.group("version")
+            versions[version] = date
+            print(f"{version}: {date}")
+
+endoflife.write_releases(PRODUCT, dict(
+    # sort by date then version (desc)
+    sorted(versions.items(), key=lambda x: (x[1], x[0]), reverse=True)
+))
+print("::endgroup::")