Update github issues to automatically report CI failures

[zakkak]

Since mandrel-bot is no longer an "admin" of the mandrel repository,
this patch uses newly created issues by mandrel-bot itself to track
failures. This way mandrel-bot can open/close the issues without any
special permission on the repository.

This should resolve issues like in https://github.com/graalvm/mandrel/actions/runs/9326678748/job/25675521613#step:5:219:

 java.io.UncheckedIOException: org.kohsuke.github.HttpException: {"message":"Must have admin rights to Repository.","documentation_url":"https://docs.github.com/rest/issues/issues#update-an-issue"}
	at Report.run(quarkus-ecosystem-issue.java:225)
	at picocli.CommandLine.executeUserObject(CommandLine.java:1769)
	at picocli.CommandLine.access$900(CommandLine.java:145)
	at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2150)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2144)
	at picocli.CommandLine$RunLast.handle(CommandLine.java:2108)
	at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:1975)
	at picocli.CommandLine.execute(CommandLine.java:1904)
	at Report.main(quarkus-ecosystem-issue.java:364)
Caused by: org.kohsuke.github.HttpException: {"message":"Must have admin rights to Repository.","documentation_url":"https://docs.github.com/rest/issues/issues#update-an-issue"}
	at org.kohsuke.github.GitHubConnectorResponseErrorHandler$1.onError(GitHubConnectorResponseErrorHandler.java:72)
	at org.kohsuke.github.GitHubClient.detectKnownErrors(GitHubClient.java:504)
	at org.kohsuke.github.GitHubClient.sendRequest(GitHubClient.java:464)
	at org.kohsuke.github.GitHubClient.sendRequest(GitHubClient.java:427)
	at org.kohsuke.github.Requester.send(Requester.java:70)
	at org.kohsuke.github.GHIssue.edit(GHIssue.java:288)
	at org.kohsuke.github.GHIssue.close(GHIssue.java:313)
	at Report.run(quarkus-ecosystem-issue.java:195)
	... 8 more