Build fix: prometheus bazel files changed. (#404)

jupp0r/prometheus-cpp#311

Author: g-easy

WORKSPACE

@@ -65,10 +65,10 @@ local_repository(
     path = "tools/zlib",
 )
 
-# Load Prometheus dependencies individually since we load some of them above.
-load("@com_github_jupp0r_prometheus_cpp//:repositories.bzl", "load_civetweb")
+# Load Prometheus dependencies.
+load("@com_github_jupp0r_prometheus_cpp//bazel:repositories.bzl", "prometheus_cpp_repositories")
 
-load_civetweb()
+prometheus_cpp_repositories()
 
 # Google APIs - used by Stackdriver exporter.
 load("@com_google_googleapis//:repository_rules.bzl", "switched_rules_by_language")