Update bazlets and bazel version

- bazlets need to be updated to react on Maven central no longer
supporting http protocol but only https
- update bazel to 2.0

Change-Id: I07f5f050f3b1db2014a5198a28b6bbf893434814
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

.bazelversion

@@ -1 +1 @@
-1.0.0
+2.0.0

WORKSPACE

@@ -20,7 +20,7 @@ check_bazel_version()
 
 load("//tools:bazlets.bzl", "load_bazlets")
 
-load_bazlets(commit = "09a035e98077dce549d5f6a7472d06c4b8f792d2")
+load_bazlets(commit = "f53f51fb660552d0581aa0ba52c3836ed63d56a3")
 
 load(
     "@com_googlesource_gerrit_bazlets//tools:maven_jar.bzl",