Add explicit provider to beta example

[slevenick]

Fixes failing test

Release Note Template for Downstream PRs (will be copied)

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 1 file changed, 1 insertion(+))
Terraform Beta: Diff ( 2 files changed, 2 insertions(+))
TF OiCS: Diff ( 1 file changed, 1 insertion(+))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=135143"

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccEndpointsService_basic You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=135147"