update: added ephemeral

Cherry pick of unmerged upstream commit that ensures a runner is
deregistered after processing a single job:

- machulav@bf49cb5

Author: Michal Šrámek

src/aws.js

@@ -15,7 +15,7 @@ function buildRunCommands(githubRegistrationToken, label) {
       `cd "${config.input.runnerHomeDir}"`,
       'source /tmp/pre-runner-script.sh',
       'export RUNNER_ALLOW_RUNASROOT=1',
-      `./config.sh --url https://github.com/${config.githubContext.owner}/${config.githubContext.repo} --token ${githubRegistrationToken} --labels ${label}`,
+      `./config.sh --url https://github.com/${config.githubContext.owner}/${config.githubContext.repo} --token ${githubRegistrationToken} --labels ${label} --ephemeral`,
     ];
   } else {
     userData = [
@@ -28,7 +28,7 @@ function buildRunCommands(githubRegistrationToken, label) {
       'curl -O -L https://github.com/actions/runner/releases/download/v${RUNNER_VERSION}/actions-runner-linux-${RUNNER_ARCH}-${RUNNER_VERSION}.tar.gz',
       'tar xzf ./actions-runner-linux-${RUNNER_ARCH}-${RUNNER_VERSION}.tar.gz',
       'export RUNNER_ALLOW_RUNASROOT=1',
-      `./config.sh --url https://github.com/${config.githubContext.owner}/${config.githubContext.repo} --token ${githubRegistrationToken} --labels ${label}`,
+      `./config.sh --url https://github.com/${config.githubContext.owner}/${config.githubContext.repo} --token ${githubRegistrationToken} --labels ${label} --ephemeral`,
     ];
   }
   if (config.input.runAsUser) {