Apply suggested fix to tetra.gemspec from Copilot Autofix

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

Author: nodeg

tetra.gemspec

@@ -6,7 +6,7 @@ Gem::Specification.new do |spec|
   spec.name        = "tetra"
   spec.version     = Tetra::VERSION
   spec.authors     = ["Dominik Gedon", "Silvio Moioli"]
-  spec.email       = ["dominik.gedon@suse.com"]
+  spec.email       = ["dominik.gedon@suse.com", "silvio.moioli@suse.com"]
   spec.homepage    = "https://github.com/uyuni-project/tetra"
   spec.summary     = "A tool to package Java projects"
   spec.description = <<~TEXT