docs(repositories): corrected gpg signingn key for newer rhel systems

On newer RHEL systems SHA1 keys are no longer supported: https://www.redhat.com/en/blog/rhel-security-sha-1-package-signatures-distrusted-rhel-9

related issue: elastic/elasticsearch#85876

Solution: elastic/elasticsearch#85876 (comment)

libbeat/docs/repositories.asciidoc

@@ -151,7 +151,7 @@ To add the {repo} repository for YUM:
 +
 [source,sh]
 --------------------------------------------------
-sudo rpm --import https://packages.elastic.co/GPG-KEY-elasticsearch
+sudo rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch
 --------------------------------------------------
 
 . Create a file with a `.repo` extension (for example, `elastic.repo`) in