Update DependabotSecretsSelectedRepoIDs type to []int64

[jburandt]

According to the docs, the API for setting a repos access to dependabot secrets is expecting an array of integers.

https://docs.github.com/en/rest/dependabot/secrets?apiVersion=2022-11-28#set-selected-repositories-for-an-organization-secret

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[gmlewis]

Thank you, @jburandt !
LGTM.

Awaiting second LGTM+Approval from any other contributor to this repo before merging.

[codecov]

Codecov Report

Merging #2794 (c800c9f) into master (d6880db) will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@## master #2794 +/- ##
=======================================
Coverage 98.06% 98.06% =======================================
Files 132 132 Lines 11650 11650 =======================================
Hits 11424 11424 Misses 154 154 Partials 72 72 

Impacted Files	Coverage Δ
github/dependabot_secrets.go	100.00% <ø> (ø)

[valbeat]

LGTM!

[gmlewis]

Thank you, @valbeat !
Merging.