Fix YAML replacing on: with true: in github workflow

[agrare]

(byebug) pp github_workflow_yml_content
"---\n" +
"name: Cross Repo Tests\n" +
"on:\n" +
"- pull_request\n" +
"jobs:\n" +
"  cross-repo:\n" +
"    uses: ManageIQ/manageiq-cross_repo/.github/workflows/manageiq_cross_repo.yaml@master\n" +
"    with:\n" +
"      test-repos: '[\"foo\", \"bar\"]'\n" +
"      repos: repo1,repo2\n"

[agrare]

Fix for invalid github actions workflow file being built: https://github.com/ManageIQ/manageiq-cross_repo-tests/pull/584/files#diff-944291df2c9c06359d37cc8833d182d705c9e8c3108e7cfe132d61a06e9133ddL3-R4

[miq-bot]

Checked commit agrare@8473885 with ruby 2.6.7, rubocop 1.19.1, haml-lint 0.35.0, and yamllint
1 file checked, 0 offenses detected
Everything looks fine. 🍰