if go.mod exists, run go get ./... first, then only run gosec if go g…

…et ./... succeeds

lib/salus/scanners/gosec.rb

@@ -13,7 +13,15 @@ def run
       shell_return = Dir.chdir(@repository.path_to_repo) do
         # sometimes the go.sum needs to be forced updated to be able to correctly build packages.
         # forcing go get seems to do the trick
-        run_shell("go get ./...")
+        if File.size?('go.mod')
+          go_get_ret = run_shell("go get ./...")
+          if go_get_ret.status != 0
+            go_get_err = "Unable to start gosec because go get ./... failed. #{go_get_ret.stderr}"
+            report_error(go_get_err, status: go_get_ret.status)
+            report_stderr(go_get_err)
+            return report_failure
+          end
+        end
         cmd = "gosec #{config_options}-fmt=json ./..."
         run_shell(cmd)
       end