Update bufbuild/buf Docker tag to v1.49.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
bufbuild/buf	final	minor	1.48.0 -> 1.49.0

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Release Notes

bufbuild/buf (bufbuild/buf)

v1.49.0

Compare Source

• Fix buf plugin push --label to allow pushing a plugin with a label.
• Add --digest-changes-only flag to buf registry {module,plugin} commit list to filter
  out commits that have no digest changes.
• Fix buf plugin push --source-control-url to allow pushing a plugin with the source
  control url.

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