Let agent retry to connecting to server (#1728)

Closes https://github.com/woodpecker-ci/woodpecker/issues/1721

PR introduces connection retries during agent startup.

Signed-off-by: Alexander Matyushentsev <AMatyushentsev@gmail.com>

cmd/agent/main.go

@@ -29,7 +29,7 @@ func main() {
 	app.Name = "woodpecker-agent"
 	app.Version = version.String()
 	app.Usage = "woodpecker agent"
-	app.Action = loop
+	app.Action = runWithRetry
 	app.Commands = []*cli.Command{
 		{
 			Name:   "ping",