chore(all): auto-regenerate .pb.go files (googleapis#843)

This is an auto-generated regeneration of the .pb.go files by
cloud.google.com/go/internal/gapicgen. Once this PR is submitted, genbot will
update the corresponding PR to depend on the newer version of go-genproto, and
assign reviewers. Whilst this or any regen PR is open in go-genproto, genbot
will not create any more regeneration PRs. If all regen PRs are closed,
gapicgen will create a new set of regeneration PRs once per night.

If you have been assigned to review this PR, please:

- Ensure that CI is passing. If it's failing, it requires your manual attention.
- Approve and submit this PR if you believe it's ready to ship. That will prompt
genbot to assign reviewers to the google-cloud-go PR.

Corresponding google-cloud-go PR: googleapis/google-cloud-go#6288

Changes:

feat: Update minimum Ruby version to 2.6
  PiperOrigin-RevId: 458023995
  Source-Link: googleapis/googleapis@d1c0171

fix: Revert Enable REST transport for Cloud Bigtable
  PiperOrigin-RevId: 458022604
  Source-Link: googleapis/googleapis@e5507fc

chore: regenerate API index

  Source-Link: googleapis/googleapis@98698f5

feat: add options for library generation in C#, PHP and Ruby docs: clarify possible transaction types and API type enum values in several APIs
  PiperOrigin-RevId: 458016835
  Source-Link: googleapis/googleapis@203c38e

docs(dataflow): corrected the Dataflow job name regex
  PiperOrigin-RevId: 458015583
  Source-Link: googleapis/googleapis@9b7d76e

docs(dialogflow/cx): clarify descriptions of the AdvancedSettings and WebhookRequest data types
  PiperOrigin-RevId: 458000126
  Source-Link: googleapis/googleapis@c425ac6

regen.txt

@@ -1 +1 @@
-79287704c3d7c2f239b52ecfb74b2efaf7e675d2
+d1c01713e381795c4326add53178368a93853ad1