docs: Add documentation for enums (#481)

* docs: Add documentation for enums

fix: Add context manager return types

chore: Update gapic-generator-python to v1.8.1
PiperOrigin-RevId: 503210727

Source-Link: googleapis/googleapis@a391fd1

Source-Link: https://github.com/googleapis/googleapis-gen/commit/0080f830dec37c3384157082bce279e37079ea58
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* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* work around docs issue

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <[email protected]>

Author: gcf-owl-bot[bot]

dlp/generated_samples/snippet_metadata_google.privacy.dlp.v2.json

@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-dlp",
-    "version": "3.11.0"
+    "version": "0.1.0"
   },
   "snippets": [
     {