Undo dependency bump in GoReleaser workflow

PiperOrigin-RevId: 410066904
Change-Id: I53d562ce3afd40b2dc3f4d6763d38941829ed8be

Update docs with new Cloud KMS Viewer role

The addition of the new Cloud KMS Viewer IAM role renders the Cloud
KMS Admin role obsolete. This commit updates documentation to refer
to the Cloud KMS Viewer role, which grants a more limited subset of
permissions while still allowing STET to look up key metadata.

PiperOrigin-RevId: 401865645
Change-Id: Ibebe97150d47748d8f18584ab45c60949ab0a9a0