fix: Update script that triggers demo project builds

[surpher]

Updates the build_children.sh script and build.yml workflow to trigger builds in demo projects' repos and fails with non-zero when a curl command fails.

📝 Summary of Changes

Changes proposed in this pull request:

• Rename triggerBuild method to triggerTravisCIBuild
• Add triggerGitHubActionsBuild
• Updates the arguments for triggerGitHubActionsBuild
• Makes the script/build fail if any curl request fails
• Runs jobs concurrently (except build_children) to save on build times

🧐🗒 Reviewer Notes

• The token for GitHub has been added to this repo's secrets

🔨 How To Test

• [ ] CI passes
• [ ] Demo projects' builds are triggered in GitHub Actions for surpher/
• [ ] Build in demo projects is postfixed with the commit message
• [ ] Demo projects' builds are triggered in TravisCI for andrewspinks

[surpher]

Closing this PR due to builds always failing when trying to PR from a fork. Will open a new PR from this repo's branch which passes all checks.